Programme and Abstract Book - Research Center for Astronomy ...

Programme and Abstract Book 

Rhodes, Greece 

12 ‐ 16 September 2011

ESPM-13 

Editors: K. Tziotziou & C. Gontikakis 

Published by: European Physical Society 

Series Editor: Prof. O. Scholten, Groningen 

Managing Editor: P. Helfenstein, Mulhouse 

europhysics 

conference 

abstracts 

35F 

ISBN 2-914771-70-3

13 th ESPM 


12 – 16 September 2011 

European 

Solar 

Physics 

Meeting 

ABSTRACTS 

Editors: K. Tziotziou & C. Gontikakis 

ORGANIZING COMMITTEE: 

S. Poedts (President), V. Nakariakov (Vice-President), G. Cauzzi, M. Collados, N. Crosby, 

L. Fletcher, K. Galsgaard, M. Georgoulis, A. Hanslmeier, V. Melnikov, D. Mueller, H. Peter, 

S. Pohjolainen, P Rudawy, J. Trujillo-Bueno, A. Veronig 

CONTACT ADDRESS: 

Research Center for Astronomy and Applied Mathematics, 

Soranou Efesiou 4, Athens, GR-11527, Greece 

Tel: +30 2106597648, Fax: +30 2106597602 

email: espm13@academyofathens.gr

13th European Solar Physics Meeting 


12 – 16 September 2011 

Programme and Abstract Book 

Edited by K. Tziotziou & C. Gontikakis

ESPM-13 Programme and Abstract Book 1 

Scientific Organising Committee 

S. Poedts (BE - Chair), L. Fletcher (UK), K. Galsgaard (DK), G. Cauzzi (IT), M. Georgoulis (GR), 

V. Melnikov (RU), D. Mueller (NL), V. Nakariakov (UK), H. Peter (DE), P Rudawy (PL), J. Trujillo- 

Bueno (ES), A. Veronig (AT) as well as A. Hanslmeier (AT - JOSO), S. Pohjolainen (FI - CESRA), 

N. Crosby (BE - SWWT), M. Collados (EAST) 

Local Organising Committee 

M. Georgoulis (Co-chair, RCAAM Academy of Athens), G. Tsiropoula (Co-chair, National Observatory 

of Athens), C. Gontikakis (RCAAM Academy of Athens), S. Patsourakos (University of Ioannina), 

K. Tziotziou (RCAAM Academy of Athens & National Observatory of Athens), L. Vlahos (University of 

Thessaloniki) 

Sponsoring Institutions and Companies 

European Solar Physics Division, Academy of Athens, National Observatory of Athens, European Space 

Agency, Solar and Heliospheric Observatory, The European Association for Solar Telescopes (EAST), 

The European Physical Society, SOTERIA project


.


Contents 

Preface 5 

Conference Programme 7 

Sunday, 11 September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Monday, 12 September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

Tuesday, 13 September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Wednesday, 14 September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Thursday, 15 September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

Friday, 16 September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Talks 15 

Session 1: Science with Cutting-Edge Heliospheric Missions . . . . . . . . . . . . . . . . . . . . 15 

Session 2: The Science of Future Heliospheric Missions and Telescopes . . . . . . . . . . . . . . 21 

Session 3: The Sun as a Whole: Large-Scale Flows, Helioseismology, Magnetism, and the Solar 

Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

Session 4: Emergence and Evolution of Magnetic Flux in the Solar Atmosphere . . . . . . . . . 33 

Session 5: Chromospheric and Coronal Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 

Session 6: Transient Activity and Seismology of the Solar Atmosphere . . . . . . . . . . . . . . 51 

Session 7: Solar Instabilities, Flares, and Coronal Mass Ejections . . . . . . . . . . . . . . . . . 57 

Session 8: Origin and Properties of the Solar Wind . . . . . . . . . . . . . . . . . . . . . . . . . 71 

Session 9: Solar Data Assimilation and Space Weather Research . . . . . . . . . . . . . . . . . 75 

Posters (per session, in alphabetical order) 81 

Section 1: Science with Cutting-Edge Heliospheric Missions . . . . . . . . . . . . . . . . . . . . 83 

Section 2: The Science of Future Heliospheric Missions and Telescopes . . . . . . . . . . . . . . 86 

Section 3: The Sun as a Whole: Large-Scale Flows, Helioseismology, Magnetism, and the Solar 

Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 

Section 4: Emergence and Evolution of Magnetic Flux in the Solar Atmosphere . . . . . . . . . 97 

Section 5: Chromospheric and Coronal Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 

Section 6: Transient Activity and Seismology of the Solar Atmosphere . . . . . . . . . . . . . . 122 

Section 7: Solar Instabilities, Flares, and Coronal Mass Ejections . . . . . . . . . . . . . . . . . 129 

Section 8: Origin and Properties of the Solar Wind . . . . . . . . . . . . . . . . . . . . . . . . . 156 

Section 9: Solar Data Assimilation and Space Weather Research . . . . . . . . . . . . . . . . . 158 

List of participants (in alphabetical order) 163


.


Dear Colleague, 

Preface 

The Board of the newly formed European Solar Physics Division, serving also as the Scientific Organizing 

Committee, and the Local Organizing Committee of the 13th European Solar Physics Meeting welcome 

you to this thirteenth meeting of the ESPM series at the cosmopolitan Greek island of Rhodes. 

Organized every three years, ESPMs welcome contributions from all aspects of contemporary solar 

physics. As you will notice browsing through this Programme, the ESPM-13 list of topics is designed to 

expose the breadth and diversity of current research in the field undertaken both in Europe and at international 

level. At the same time, as this list cannot possibly be exhaustive, more general contributions 

not necessarily falling into these categories are also accommodated in the Programme. 

Long-time solar physicists can hardly remember any more exciting times in the field. An armada of 

missions with outstanding performance have filled our data reservoirs with vast amounts of pristine solar 

data. A host of new missions just launched or to be launched in the short-to-mid term promise to 

raise the level and the expectations of the once data-starved community even more. At the same time, 

technological breakthroughs have made it possible to obtain exemplary solar observations even from the 

ground. As a result, cutting-edge facilities appear around the globe. Hoping to inspire young scientists 

and to attract even more, much-needed, brilliant minds into the field, the ESPM-13 devotes its first two 

sessions to the science of existing and future missions and facilities. The meeting also exploits the idea of 

invited contributions in addition to invited reviews to allow more experts to present recent work without 

necessarily incurring a burden on contributed presentations. A large number of posters complete the 

Science Programme and the organization has allowed ample opportunities for poster viewing in prime 

time within each meeting day. Moreover, each session has a non-uniform floor time weighted by the 

interest the session attracted in terms of number of submitted abstracts. The meeting concludes by 

discussing the response of the solar physics community to a key interdisciplinary challenge of our time: 

the science of space weather and solar data assimilation as viewed from the solar end of the phenomenon. 

Let us now spend a few words on Rhodes, the meeting’s host island: Rhodes is the largest island of the 

Dodecanese Archipelago and also one of the largest and most well-known Greek islands. It is located at the 

crossroad between three continents; Europe, Asia, and Africa, and along the marine routes that connect 

the West with the Orient. Given its strategic location the island attracted various populations and was 

influenced by several cultures in the course of its multi-millennium history. Known to be inhabited since 

the Neolithic Era, the island was already famous at the dawn of the historical times as the land of three 

powerful cities: Lindos, Ialysos and Kameiros, as described by Homer. The island also became famous 

worldwide as the home of one of the Seven Wonders of the Ancient World - the Colossus of Rhodes. At 

a height of nearly 33 meters (almost 110 feet), the giant statue was made of bronze and was reportedly 

erected at the entrance of the ancient port of Rhodes in 280 BC. No trace of the statue remains today as 

it was destroyed by an earthquake in 224 BC. In medieval times the Venetians fortified the city to protect 

it from enemies and pirates and facilitated numerous public works, while the Knights of the Order of St. 

John of Jerusalem bought the island in the 14th century and gave the fortifications the Gothic aesthetics 

they have today. The Old Town of Rhodes, declared a World Heritage Monument by UNESCO, is the 

largest inhabited medieval town in Europe while its fortifications are considered by experts as the finest 

example of medieval architecture. Let us mention at this point that according to Greek mythology, Zeus 

(leader of the ancient Greek Gods) decided to divide the earth among Gods. The Sun God Helios chose 

Rhodes as it emerged from the azure blue sea, bathed it with his eternal light and made it one of the 

most beautiful islands of the Aegean. Helios named the island after the nymph Rhode with whom he 

was married and they both became its protectors. 

In ancient times Rhodes was therefore known as “the island of Sun” - what better reason one might find 

to organize the central European solar physics meeting in this privileged land! 

At this point let us express our gratitude to our generous sponsors without whom the organization of 

ESPM-13 would not be possible: the Academy of Athens and the National Observatory of Athens, cohosting 

institutions, the European Physical Society, host organization of the European Solar Physics


Division, the European Space Agency and, in particular, the Solar and Heliospheric Observatory, the 

European Association of Solar Telescopes, and the SOTERIA Project of the European Commission. 

But most of all, let us thank you for your interest and participation in the ESPM-13. We wholeheartedly 

wish you a productive, inspiring, but also enjoyable and memorable meeting! 

Manolis Georgoulis and Georgia Tsiropoula 

On behalf of the SOC and the LOC


Conference Programme 

Sunday, 11 September 2011 

17:30 - 21:00 Secretariat opens - Registration 

20:00 - 21:30 Welcome cocktail (Rodos Palace Hotel) 

Morning session: 

Monday, 12 September 2011 

08:00 Secretariat opens 

08:45 - 09:00 Welcome address (S. Poedts & the LOC) 

Session 1: Science with Cutting-Edge Heliospheric Missions 

Chairman: S. Poedts 

09:00 - 09:30 The first sixteen months of solar dynamics observatory science (Invited) 

D. Pesnell 

09:30 - 10:00 Full-Sun observations from STEREO: Recent results and future science opportunities 

(Invited) 

A. Vourlidas 

10:00 - 10:30 Science with Hinode (Invited) 

L. Harra 

10:30 - 11:10 Coffee Break & Poster Viewing 

11:10 - 11:40 The Quiet Sun as seen by SUNRISE (Invited) 

V. Martinez-Pillet 

11:40 - 12:10 Science with ground-based telescopes (Invited) 

L. Rouppe van der Voort 

12:10 - 12:30 PROBA 2/SWAP & LYRA: First Results and Opportunities for Solar Physics 

and Space Weather (Invited) 

A. De Groof 

12:30 - 14:00 Lunch Break 

Afternoon session: 

Session 2: The Science of Future Heliospheric Missions and Telescopes 

Chairman: J. Trujillo-Bueno 

14:00 - 14:30 Science with EST, the ATST, and other ground-based facilities (Invited) 

W. Schmidt 

14:30 - 15:00 Solar physics and space weather with the Low-Frequency Array (LO- 

FAR)(Invited) 

G. Mann 

15:00 - 15:30 Science and synergies of Solar Orbiter and Solar Probe plus missions (Invited) 

E. Antonucci 

15:30 - 15:50 The science of Solar-C (Invited) 

S. Tsuneta 

15:50 - 17:00 Coffee Break & Poster Viewing


17:00 - 17:15 LEMUR (Large European Module for solar Ultraviolet Research): The VUV 

imaging spectrograph for the JAXA’s Solar-C mission 

L. Teriaca 

17:15 - 17:30 The SPARK mission: Understanding particle acceleration extremes on our 

nearest star 

D. Williams 

17:30 - 17:45 Measuring magnetic fields in the outer atmosphere - SolmeX 

H. Peter 

Session 3: The Sun as a Whole: Large-Scale Flows, Helioseismology, Magnetism, and the Solar Cycle 

Chairman: H. Peter 

17:45 - 18:00 Sunspot groups and the global magnetic field of the Sun 

P. Higgins 

18:00 - 18:15 Solar irradiance over the last three cycles 

N.A. Krivova 



Tuesday, 13 September 2011 

Session 3: The Sun as a Whole: Large-Scale Flows, Helioseismology, Magnetism, and the Solar Cycle 

Chairman: H. Peter 

09:00 - 09:30 A review on helioseismology and connections with asteroseismology (Invited) 

M. Roth 

09:30 - 09:50 Implications of solar wind magnetic helicity for dynamo theory (Invited) 

A. Brandenburg 

09:50 - 10:05 Multitude of scales in distribution of helicity of solar magnetic fields over the 

magnetic cycle 

K. Kuzanyan 

10:05 - 10:20 Are the magnetic fields in the solar internetwork region horizontal or isotropic? 

J.M. Borrero 

10:20 - 10:35 Supersonic horizontal flows in the solar granulation 

L.R. Bellot Rubio 


Session 4: Emergence and Evolution of Magnetic Flux in the Solar Atmosphere 

Chairman: C. Alissandrakis 

11:30 - 12:00 Magnetic flux emergence: a precursor of solar dynamic phenomena (Invited) 

V. Archontis 

12:00 - 12:15 New insights into the origin and evolution of coronal mass ejections 

I. Roussev 

12:15 - 12:30 Are chromospheric swirls channeling energy from the photosphere into the 

corona? 

S. Wedemeyer-Bohm 

12:30 - 14:00 Lunch Break



14:00 - 14:20 Observational investigations of magnetic fields and their emergence in the solar 

atmosphere (Invited) 

A. Asensio-Ramos 

14:20 - 14:35 High-resolution observations of small-scale magnetic flux emergence at the photosphere 

and response of the upper atmospheric layers 

S. Guglielmino 

14:35 - 14:50 On the shapes of stokes V profiles emerging in the quiet Sun 

B. Viticchié 

14:50 - 15:05 Solar pore: relations between magnetic and velocity fields 

M. Sobotka 

15:05 - 15:20 The sunspot moat flow as seen with HMI/SDO 

R. Schlichenmaier 

15:20 - 15:35 Flocculent flows in superpenumbral fibrils: a new view on the inverse Evershed 

effect? 

G. Vissers 

15:35 - 15:50 Dynamo-driven plasmoid ejections above a spherical surface 

J. Warnecke 


Session 5: Chromospheric and Coronal Heating 

Chairman: G. Cauzzi 

17:00 - 17:30 A progress report on coronal heating (Invited) 

J. Klimchuk 

17:30 - 17:45 3D simulations of wave heating: where is all the energy? 

I. De Moortel 

17:45 - 18:00 Scale invariant coronal heating by (nano-)flares in a 3D MHD model 

S. Bingert 

18:00 - 18:15 Signatures of impulsive coronal heating in warm and hot spectral lines 

S. Patsourakos 

18:15 - 18:30 Cool loops contribution to the transition region EUV output 

C. Sasso 

20:00 - 22:00 ESPD Business meeting




Wednesday, 14 September 2011 

Session 5: Chromospheric and Coronal Heating 

Chairman: G. Cauzzi 

09:00 - 09:20 What can we learn about coronal heating from spicules? (Invited) 

B. De Pontieu 

09:20 - 09:35 Mass transport in the solar atmosphere 

N. Guerreiro 

09:35 - 09:50 Ejection of cool plasma into the hot corona 

P. Zacharias 

09:50 - 10:05 Helicity in spicules and explosive events 

W. Curdt 

10:05 - 10:20 A rainy day on the Sun 

P. Antolin 

10:20 - 10:35 Partial ionization effects in the solar photosphere and chromosphere 

M. Collados 


11:15 - 11:30 Realistic simulations of the impact of partial ionization on the chromosphere 

J. Martinez-Sykora 

11:30 - 11:45 Wave propagation in the solar atmosphere: explaining observations with a 

single model 

M. Stangalini 

11:45 - 12:00 The temperature structure of the solar chromosphere 

J. Leenaarts 

12:00 - 12:15 The chromospheric solar sub-millimeter cavity and the minimum temperature 

V.H. De la Luz Rodriguez 

12:15 - 13:00 Quick Lunch 

13:00 - 21:00 Rhodes island excursion (Optional) or Free afternoon




Thursday, 15 September 2011 

Session 6: Transient Activity and Seismology of the Solar Atmosphere 

Chairman: V. Nakariakov 

09:00 - 09:30 New developments in coronal seismology (Invited) 

T. van Doorsselaere 

09:30 - 09:45 Bayesian inversion technique for seismology of the solar atmosphere 

I. Aregui 

09:45 - 10:05 Oscillations and wave propagation in the solar atmosphere (Invited) 

E. Khomenko 

10:05 - 10:20 The chromospheric magnetic field and the determination of the height of the 

magnetic canopy 

I. Kontogiannis 

10:20 - 10:35 Three-minute oscillations above sunspot umbra observed with SDO and NoRH 

V. Reznikova 

10:35 - 10:50 Frequency drifts of three-minute oscillations in microwave and EUV above 

sunspots 

R. Sych 


Session 7: Solar Instabilities, Flares, and Coronal Mass Ejections 

Chairman: V. Melnikov 

11:30 - 12:00 Particle acceleration in flares and CMEs (Invited) 

L. Klein 

12:00 - 12:15 SEP events and associated phenomena in the corona and IP space 

R. Miteva 

12:15 - 12:30 Instability of electrons trapped by coronal magnetic field and its evidence in 

the fine structure of solar radio spectra 

E. Zlotnik 

12:30 - 14:00 Lunch Break 


14:00 - 14:15 Solar flares at millimeter and submillimeter wavelengths 

G. Trottet 

14:15 - 14:30 Diagnostics of electron transport in the chromosphere using hard X-ray solar 

flare observations 

M. Battaglia 

14:30 - 14:50 Measurements of Solar flare anisotropy using RHESSI 

E. Dickson 

14:50 - 15:05 Particle acceleration in unstable twisted coronal loops 

M. Gordovskyy 

15:05 - 15:20 Constraining turbulent acceleration models with imaging observations of thick 

target coronal loops 

N. Bian


15:20 - 15:35 The Multifrequency Siberian Radioheliograph 

S.V. Lesovoi 

15:35 - 15:50 Microwave study of coronal sources in the early rise phase of solar flares 

A. Altyntsev 


17:00 - 17:15 Study of flare energy release using events with numerous type III-like bursts in 

microwaves 

N. Meshalkina 

17:15 - 17:30 The effect of self-induced electric field of electron beams on generation of Langmuir 

turbulence and resulting MW emission in flares 

V. Zharkova 

17:30 - 17:45 3D solar null point acceleration simulation 

G. Baumann 

17:45 - 18:00 Slow magnetoacoustic waves in two-ribbon flares 

V. Nakariakov 

18:00 - 18:15 Magnetoacoustic shock formation near a magnetic null point 

M. Gruszecki 


20:00 - 23:00 Conference Dinner 


Friday, 16 September 2011 

Session 7: Solar Instabilities, Flares, and Coronal Mass Ejections 

Chairman: A. Veronig 

09:00 - 09:20 Initiation and early evolution of CMEs: a numerical approach (EPS Invited 

Speaker) 

C. Jacobs 

09:20 - 09:35 Magnetic topology of sigmoid regions: comparison of a NLFFF extrapolation 

and a MHD simulation 

E. Pariat 

09:35 - 09:50 Simulated CMEs with multiple reconnection sites: a model for particle injection 

S. Masson 

09:50 - 10:05 Solar eruptions and the overlying background magnetic field 

A. Nindos 

10:05 - 10:20 Coronal Mass Ejection - Flare relationship and the topology of the erupting 

field 

B. Kliem 

10:20 - 10:35 Multi-spacecraft study of the kinematics of a coronal mass ejection and its 

associated shock: EUV, white light, and radio signatures 

V. Ontiveros 

10:35 - 11:15 Coffee Break & Poster Viewing


11:15 - 11:30 The mechanisms for CME onset and particle acceleration 

S. Antiochos 

11:30 - 11:45 Linking remote-sensing and in-situ observations of coronal mass ejections using 

STEREO 

L. Rodriguez 

11:45 - 12:00 Analysis of the characteristic coronal plasma parameters using homologous 

large-scale EUV waves 

I. W. Kienreich 

12:00 - 12:15 3D MHD numerical simulations of dome-shaped EUV waves from rotating active 

regions 

M. Selwa 

12:15 - 13:45 Lunch Break 


Session 8: Origin and Properties of the Solar Wind 

Chairman: M. Georgoulis 

13:45 - 14:15 Origin and properties of the solar wind(Invited) 

E. March 

14:15 - 14:30 Transients in the solar wind and their soar origin during the solar activity 

minimum 

E. Kilpua 

14:30 - 14:45 Large-scale variations of the solar wind electron properties from quasi-thermal 

noise spectroscopy: Ulysses measurements 

G. Le Chat 

14:45 - 15:00 Plasma properties and evolution of brightenings in coronal holes and the quiet 

Sun from XRT, EIS, SOT, and SUMER co-observations 

M. Madjarska 


Session 9: Solar Data Assimilation and Space Weather Research 

Chairman: P. Rudawy 

15:40 - 16:10 Current standing of space-weather forecasting (Invited) 

E. Robbrecht 

16:10 - 16:25 Solar energetic particle research at IAA/NOA: a space weather perspective 

O. Malandraki 

16:25 - 16:40 The influence of ambient solar wind flow on the propagation behavior of interplanetary 

CMEs 

M. Temmer 

16:40 - 17:00 Image processing pattern recognition, and data assimilation in the SDO era 

(Invited) 

A. Davey 

17:00 - 17:15 Solar flare forecasting: from probabilities to targeted predictions 

D.S. Bloomfield 

17:15 - 17:30 A new solar prominence catalogue with SOPRA 

N. Labrosse 

17:30 - 17:40 Meeting’s summary & closing address (S. Poedts)


.


Session 1 

Science with Cutting-Edge Heliospheric Missions


.


The First Sixteen Months of Solar Dynamics Observatory 

Science 

Invited review 

W. Dean Pesnell 1 

1 Code 671 NASA, Goddard Space Flight Center Greenbelt, Maryland, 20771 USA 

Abstract 

The Solar Dynamics Observatory (SDO) was launched on February 11, 2010 into partly cloudy 

skies over Cape Canaveral, Florida. SDO is now in a 28 degree inclined geosynchronous orbit at the 

longitude of New Mexico and began returning science data May 1, 2010. There are three instruments 

on SDO. EVE measures the Heartbeat of Space Weather, the extreme ultraviolet output of the Sun 

that causes much of Space Weather. Another instrument, AIA, allows us to follow solar plasma as 

it speeds along its roller coaster ride and creates that solar output. The loops and whirls seen in 

AIA images are caused by plasma moving along magnetic fields. These fields will be measured as 

they erupt through the surface of the Sun by HMI, our third instrument. HMI will also measure 

sound waves rippling across the face of the Sun, allowing us to build ultrasounds of the Sun that 

peer into and through the Sun. Early results from SDO include quantifying the total energy from 

flares, examining the response of the global Sun to locally small perturbations, and detailed looks at 

erupting prominences. This talk will discuss the building and launch of SDO and how SDO data is 

changing how we see the Sun, inside and out. 

Full-Sun Observations from STEREO: Recent Results and 

Future Science Opportunities 


A. Vourlidas 1 

1 Space Sciences Division, Naval Research Laboratory, Washington, DC, USA 


STEREO is continuing its comprehensive observation of the Sun and inner heliosphere from two 

vantage points. The unique mission design has given us an ever-changing view of activity in the low 

corona and outer heliosphere. STEREO observations have uncovered the true size, kinematics and 

morphology of Coronal Mass Ejections, recorded the genesis of impulsive CMEs and associated waves, 

and even improved the accuracy of space weather predictions. In February 2011, the two STEREO 

spacecraft reached opposition and began to observe the full 360 deg solar corona, right on time for the 

next solar maximum. In this talk, I review some of the early STEREO results since full sun coverage 

began and describe the intriguing possibilities for new science during the upcoming solar maximum.


Science with Hinode 


L.K. Harra 1 

1 UCL-Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, RH5 6NT, UK. 


The Hinode mission is in its fifth year of observations. The scientific results have covered small 

scale magnetic phenomena in different regions of the Sun, coronal holes, solar cycle effects, solar wind 

formation (both fast and slow) and the triggering of solar flares and coronal mass ejections. I will 

summarize the results to date and discuss plans for future observing. 

The Quiet Sun as Seen by Sunrise 


V. Martinez-Pillet 1 

1 IAC 


The SUNRISE balloon flight in June 2009 observed the surface of the Sun with a spatial resolution 

in the range of 100-200 km for several periods, lasting typically 30-40 minutes, and with cadences 

of tenths of seconds. The high sensitivity IMaX vector magnetograms and the near UV images are 

being used to increase our understanding of the quiet-sun dynamics. At this spatial resolution ”adhoc” 

factors used in inversion codes such as microturbulence or filling factors start to loose their 

meaning. KiloGauss fields are directly inferred by simply the amplitude of the observed polarization 

signals. The time cadence of the IMaX data (30 seconds) allows to observe dynamical events such as 

supersonic jets that indicate reconnection between newly emerged fields and preexisting fields at the 

surface. These jets explain a large fraction of the observed anomalous Stokes signals in the quiet sun. 

The benefits from improved spatial and time resolutions are evident. 

Science with Ground-Based Telescopes 


L. Rouppe Van der Voort 1 

1 UiO 


In recent years, adaptive optics and image reconstruction techniques have become standard tools 

at the major ground-based solar telescopes. This development has greatly enhanced the chances of 

obtaining high-quality data sets from ground-based facilities that frequently suffer from the torments 

of seeing. It has also boosted the potential of Fabry-Perot imaging interferometers. These instruments 

allow fast wavelength switching and provide detailed spectral and polarimetric information over an 

extended field of view. High resolution can now be achieved simultaneously in the spatial, temporal 

and spectral domains over extended periods of time. Such multi-dimensional data sets constitute a 

gold-mine for scientific analysis. In this review, I will discuss the latest developments and highlight 

some of the scientific results achieved with Fabry-Perot instruments.


PROBA2/SWAP & LYRA: First results and opportunities 

for solar physics and space weather 

Invited contribution 

A. De Groof 1 , D. Berghmans 2 , M. Dominique 2 & Science Consortium 

for SWAP & LYRA 

1 European Space Agency, Department of Science and Robotic Exploration c/o Royal Observatory of Belgium 

2 Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium 


PROBA2 is an ESA micro-satellite, launched on November 2, 2009 from Russia. PROBA2 carries 

two solar monitoring instruments, the LYRA UV radiometer and the SWAP EUV telescope for 

coronal imaging and space weather monitoring. We will give a small overview of the technical characteristics, 

performance of SWAP and LYRA and the opportunities brought by the PROBA2 platform. 

The available PROBA2 data products and services are presented concentrating on the unique complementarity 

of the SWAP images as compared to other solar EUV imagers (onboard SOHO, SDO, 

STEREO), and LYRA data as compared to other radiometers as GOES, etc. 

The first results will be discussed, giving special attention to the opportunities these instruments 

bring for solar physics. The fact that SWAP and LYRA have an open data policy and data products 

are available in near-real time makes them especially interesting, also for Space Weather. SWAP and 

LYRA can also be commanded in a very flexible manner, thanks to the unique design of the PROBA2 

Science Center. In this way, the solar community is at the steering wheel of this small satellite.


.


Session 2 

The Science of Future Heliospheric Missions and Telescopes


.


Science with the EST, the ATST, and Other 

Ground-Based Facilities 


W. Schmidt 1 

1 Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, 79104 Freiburg, Germany 


During the last four decades, the aperture and the resolution of solar telescopes have gradually 

increased. Presently, two high-resolution telescopes with apertures around 1.5 meters (the NST at 

Big Bear, and GREGOR on Tenerife) are just beginning to provide science data. The Advanced 

Technology Solar Telescope (ATST) in the US and the European Solar Telescope (EST) with their 

apertures of 4 meters mark most important milestones for ground-based solar physics. These telescopes 

will increase the photon collection capability by a factor of 10 and the resolving power by a 

factor of 3 compared to the largest presently operating telescopes. 

Near the end of this decade, the ATST will open a new perspective for solar physics, followed by the 

EST that hopefully can be realized at the beginning of the next decade. Both telescopes will feature 

science instruments specialized in high-resolution spectropolarimetry, covering the electromagnetic 

spectrum from the near UV to the thermal infrared, allowing to observe the solar atmosphere from 

the deep photosphere to the inner corona. 

Magnetic fields connect the convection zone with the inner and outer solar atmosphere and with 

interplanetary space. Magnetic structures exist on scales from a solar radius down to some ten 

kilometers. The magnetic activity of the Sun is responsible for most energetic events on the Sun and 

causes its variable brightness, which in turn influences the terrestrial climate. 

The future telescopes are designed with the prime goal to measure the solar magnetic field with 

hitherto unseen precision and resolution. With such observations we will understand how magnetic 

field is generated, and how it is removed from the solar surface. This will give insight into the 

mechanisms that produces the magnetic activity cycle and the magnetic instabilities, which in turn 

drive the Sun-Earth connection. 

Solar Physics and Space Weather with the Low 

Frequency Array (LOFAR) 


G. Mann 1 

1 Leibniz Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany 


The LOw Frequency ARray (LOFAR) is a novel radio telescope that consists of 20 core stations 

near Exloo in the Netherlands, 18 Dutch remote stations, and 8 international stations all distributed 

over central Europe. One of them was built in Potsdam. LOFAR is a radio interferometer for the 

frequency range of 30−240 MHz and will exceed the sensitivity and resolution of existing instruments 

by more than one order of magnitude. “Solar Physics and Space Weather with LOFAR” is one of 

LOFAR’s Key Science Projects. Since LOFAR is working in the frequency range of 30−240 MHz, it 

is able to deliver radio images of the Sun. The solar radio radiation in this frequency range is emitted 

from the outer corona. Since radio waves are strongly scattered in the corona, the angular resolution 

of LOFAR’s radio maps will be limited to a few 10 arcseconds. The necessary baselines include the 

core and the nearest remote stations. First results for solar observations with LOFAR during the 

commissioning phase will be presented.


Science and Synergies of Solar Orbiter and Solar Probe 

Plus Missions 


E. Antonucci 1 

1 INAF - Osservatorio Astronomico di Torino, Italy 


Two highly innovative missions, Solar Orbiter (ESA-NASA) and Solar Probe Plus (NASA), have 

been devised to study in the near future the Sun and the heliosphere, in a complementary way. 

Both missions rely on the idea of a close approach to the Sun to explore directly the outer solar 

corona and the circumsolar region, in order to fully understand how the Sun creates the solar wind 

and thus in turn it creates and controls the heliosphere. Solar Probe will explore the plasma of the 

outer corona (minimum perihelion 9-10 solar radii), with a complement of in situ instruments. Solar 

Orbiter will explore the inner heliosphere (minimum perihelion 0.28 AU) with a suite of both in situ 

and remote sensing instruments, observing the Sun, designed to ensure a full understanding of the 

connections and the coupling between the Sun and the heliosphere. In its journey, Solar Orbiter will 

leave the ecliptic plane in order to provide observations of the solar polar regions. The proximity to 

the Sun will also have the advantage that the spacecraft will fly in near synchronization with the Sun’s 

rotation. The two missions will thus jointly address, with a completely new observational approach, 

the fundamental questions of solar physics, concerning the solar dynamo, coronal heating and origin 

of the fast and slow solar wind, origin of the coronal mass ejections which drive the heliospheric 

variability and of the energetic particle radiation which fills the heliosphere. 

The Science of Solar-C 


Saku Tsuneta 1 

1 (National Astronomical Observatory of Japan) and ISAS/JAXA Solar-C Working Group 


The purpose of the Solar-C (plan B) mission is to reveal the magnetic and plasma structures 

of the whole solar atmosphere from the photosphere throughout the corona, and understand the 

mechanisms of chromospheric and coronal heating/dynamism and acceleration of the solar wind as a 

system. It is our understanding that small scale processes related to waves, shocks and reconnection 

play an important role in the global phenomena of the Sun and the heliosphere. 

Our approach to implement this science goal is through high resolution imaging spectroscopy 

for the entire solar atmosphere without gaps in temperature coverage where plasma might escape 

detection because of lack of instrumental sensitivity. Hinode clearly showed that the combination of 

high spatial resolution and spectroscopy (including spectro-polarimetry) is critically important both 

in the photosphere and in the corona. The strawman instruments for the Solar-C satellite include a 

larger visible light telescope, which obtains magnetic and velocity maps for the chromosphere and the 

photosphere, a high-throughput UV imaging spectrometer covering the chromosphere through the 

corona, and an X-ray/EUV telescope. The three instruments will seamlessly cover the photosphere 

through the corona. Such a wide spectroscopic coverage with high resolution is not available with 

any mission so far launched. The Solar-C instruments are characterized by high spatial and spectral 

resolution, high throughput, wide temperature coverage, and high time resolution, better than 

available from any existing missions. 

An Interim Report of the mission is available now. The document describes the current state 

of development for the Solar-C mission concept. As the program progresses we will continue to 

solicit new ideas and improvements to the mission definitions, especially from our colleagues outside 

Japan. We recognize that Solar-C will only be realized with the enthusiastic participation of ESA 

and European scientists in all phases its development from the conceptual design of the instruments, 

through their construction, and in the science operation of the Solar-C mission. We hope that the 

European Space Agency (ESA) will participate in the Solar-C program.


LEMUR (Large European Module for solar Ultraviolet 

Research): The VUV imaging spectrograph for the 

JAXA’s Solar-C mission. 

L. Teriaca 1 , G.A. Doschek 2 , L.K. Harra 3 , C. Korendyke 2 , 

U. Schühle 1 , T. Shimizu 4 and the LEMUR team 

1 Max-Planck-Institut für Sonnensystemforschung Max-Planck-str. 2, 37191 Katlenburg-Lindau, Germany 

2 Space Science Division, Naval Research Laboratory, Washington DC, 20375-5320, USA 

3 UCL - Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK 

4 Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, 

Kanagawa 252-5210, Japan 


Understanding the complex and extremely dynamic environment of the solar outer atmosphere 

requires concerted, simultaneous solar observations from the visible to the vacuum ultraviolet (VUV) 

and soft X-rays, at high spatial resolution (between 0.1” and 0.3”), at high temporal resolution (on 

the order of 10 s, i.e., the time scale of chromospheric dynamics), with a wide temperature coverage 

(from 5000 K to several million K in order to cover the widely disparate regimes from the solar surface 

through the chromosphere and transition region to the corona during events such as flares), and 

the capability of measuring magnetic fields through spectropolarimetry at visible and near-infrared 

wavelengths. Simultaneous spectroscopic measurements sampling the entire temperature range are 

particularly important. These requirements are fulfilled by the Japanese Solar-C mission, composed 

of a spacecraft in a geosynchronous orbit with a payload providing a significant improvement of 

imaging and spectropolarimetric capabilities in the UV, visible, and near-infrared with respect to 

what is available today and foreseen in the near future. 

The Large European Module for solar Ultraviolet Research (LEMUR) is a large VUV telescope 

feeding a scientific payload of high-resolution imaging spectrographs and cameras. LEMUR consists 

of two major components: a VUV solar telescope with a 30-cm diameter mirror and a focal length 

of 3.6 m, and a focal-plane package composed of VUV spectrometers covering six carefully chosen 

wavelength ranges between 17 nm and 127 nm. The LEMUR slit covers 280” on the Sun with 0.14” 

per pixel sampling. In addition, LEMUR is capable of measuring mass flows velocities (line shifts) 

down to 2 km/s or better. 

LEMUR has been proposed to ESA as the European contribution to the Solar C mission. 

The SPARK Mission: understanding particle acceleration 

extremes on our nearest star 

S.A. Matthews 1 , D.R. Williams 1 and the SPARK consortium 

1 Mullard Space Science Laboratory, University College London, Holmbury St Mary, Surrey, RH5 6NT, U.K. 


Energetic particles fill the universe and can tell us how that universe originated and what it is 

made of. They shape the way in which our own and other solar systems work, how planets are 

formed and what the conditions for the emergence and continuation of life might be. The process 

of particle acceleration itself is found throughout the universe in environments as diverse as stellar 

coronae, active galactic nuclei, the coronae of accretion disks around black holes, the magnetospheres 

of neutron stars and planetary atmospheres interacting with the wind of their star. Despite the 

critical role of particle acceleration in shaping the universe as we know it, the details of the physical 

processes themselves poorly understood. 

The SPARK mission (Solar Particle Acceleration Radiation and Kinetics) will primarily observe 

the Sun in order to understand the processes of particle acceleration involved and in particular its 

extremes. SPARK will make the first space measurements of the far infrared component of solar flares,


the first series of gamma-ray line images, and the most sensitive measurements yet of the hard X-ray 

(HXR) and gamma-ray spectrum, placing us ideally to make significant progress in understanding 

the roles of electric fields, shocks and wave-particle interactions in accelerating particles on the Sun. 

Measuring magnetic fields in the outer atmosphere - SolmeX 

H. Peter 1 and the SolmeX team 

1 Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany 


Current observations show an unprecedented view of the many details in the outer atmosphere of 

the Sun, almost exclusively driven by the magnetic field. However, our knowledge of the magnetic 

field in the outer solar atmosphere is to the most part restricted to extrapolations from the surface 

magnetic field. As the magnetic field is at the very heart of the physical processes, it is highly 

desirable to acquire direct measurements of the magnetic field in the outer atmosphere. 

To reach this goal we proposed a mission, SolmeX, to ESA in response to their latest call for 

an M-class mission. SolmeX would have performed spectro-polarimetric observations in the extreme 

ultraviolet (EUV), the ultraviolet (UV) and the infrared (IR). The mission proposal consisted of two 

spacecrafts, one carrying the instruments, and another one in formation flight at a distance of about 

200 m carrying the occulter to provide an artificial total solar eclipse allowing for low-scattering and 

high resolution coronal measurements. 

The instrument suite consisted of two spectro-polarimetric coronagraphs for off-limb observations, 

one in the EUV and one in the IR, and three instruments for observations on the disk. The latter 

comprised one imaging polarimeter in the EUV for coronal studies, a spectro-polarimeter in the 

EUV to investigate the low corona, and an imaging spectro-polarimeter in the UV for chromospheric 

studies. 

Current missions and upcoming missions such as IRIS or SolarOrbiter provide an amazing detail 

on the structure and dynamics. However, none of these will provide information on the polarimetric 

state of the light and thus give us the crucial information on the magnetic field jointly with the state 

of the plasmas in the outer solar atmosphere. ESA did not select SolmeX (or any other solar mission) 

for further study, but we hope that this contribution will attract the attention of more people to the 

concept of spectro-polarimetric observations in the outer solar atmosphere and stimulate a discussion 

towards a next-generation solar mission.


Session 3 

The Sun as a Whole: Large-Scale Flows, Helioseismology, 

Magnetism, and the Solar Cycle


.


Sunspot Groups and the Global Magnetic Field of the Sun 

P.A. Higgins 1 , D.S. Bloomfield 1 , and P.T. Gallagher 1 

1 Trinity College Dublin, College Green, Dublin 2, Ireland 


The Sun follows an 11 year activity cycle, over which the global magnetic field begins highly 

dipolar, and becomes more complex at cycle maximum, until reverting back to a dipole state, but with 

reversed polarity. Many magnetic structures of varying complexity, or active regions, are observed 

to emerge, evolve, and decay over the cycle. Beyond location and orientation, the dependence of 

active region magnetic properties on the phase of the solar cycle is not well known. Here, we use 

automated feature detection methods to detect and characterize thousands of active regions and 

statistically investigate their physical properties. It is found that the mean size and flux of magnetic 

features on the solar disk is dependent on the phase of the cycle. We establish a direct connection 

between the spatial distribution of active regions on the solar disk and the configuration of the global 

solar magnetic field by investigating the polarity imbalance of feature magnetic flux. Using a global 

potential field source surface model, we find that the shape of the global field is strongly dependent 

on the large scale distribution of imbalanced flux. 

Solar irradiance over the last three cycles 

N.A. Krivova 1 , S.K. Solanki 1 , W. Ball 2 , K.L. Yeo 1 , W. Schmutz 3 , 

Y.C. Unruh 2 and T. Wenzler 1,4 

1 Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany 

2 Astrophysics Group, Blackett Laboratory, Imperial College London, UK 

3 Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Switzerland 

4 Hohschule für Technik Zürich, Switzerland 


Solar irradiance has been monitored since 1978. Variations on time scales of days up to the solar 

cycle have been attributed to the evolution of the solar surface magnetic field. However, uncertainties 

in the cross-calibration of the TSI measurements by different instruments have triggered the debate 

on the presence and the magnitude of the secular trend in the TSI over the last three cycles, as well 

as on its physical cause. We employ (quasi-)simultaneous full disc magnetograms and continuum 

images recorded at the KP NSO, as well as by the SoHO/MDI and SDO/HMI instruments as input 

to our SATIRE-S model to reconstruct solar irradiance between 1974 and 2011 and to test whether 

its variations can be explained by the solar surface magnetism.


A Review on Helioseismology and Connections with 

Asteroseismology 


M. Roth 1 

1 Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, 79104 Freiburg, Germany 


Helioseismology has been tremendously successful in illuminating the physical state of the solar 

interior during the last decades thanks to dedicated projects like the Solar and Heliospheric Observatory 

(SOHO) and the Global Oscillation Network Group (GONG). 

The field is now about to take a giant leap forward with the successful launches of new space 

missions, e.g. SDO and Picard, and the development of new ground-based instruments with vastly 

better spatial and temporal resolution. This now allows making use of the full potential of helioseismic 

techniques to study the solar interior in great detail and to establish relationships between internal 

solar properties and magnetic activity in the solar atmosphere. 

However, a complete understanding of the Sun, and in particular of its magnetism, can only 

be obtained by understanding the internal structure and properties of the stars in general. Asteroseismology 

offers solving this problem by studying the interiors of the stars. As the CoRoT and 

Kepler space observatories deliver the respective high-quality data needed, now this question can be 

addressed. 

This talk will review the achievements and prospects of helioseismology, and will highlight connections 

between helio- and asteroseismology. 

Implications of solar wind magnetic helicity for 

dynamo theory 


A. Brandenburg 1,2 , K. Subramanian 3 , A. Balogh 4,5 , & M. L. Goldstein 6 

1 NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden 

2 Department of Astronomy, Stockholm University, SE-10691 Stockholm, Sweden 

3 IUCAA, Post bag 4, Ganeshkhind, Pune 411 007, India 

4 International Space Science Institute, Hallerstrasse 6, Bern CH-3012, Switzerland 

5 Space and Atmospheric Group, Blackett laboratory, Imperial College, London, United Kingdom 

6 Code 673, NASA-Goddard Space Flight Center, Greenbelt, Maryland 20771, USA 


In a recent paper (Brandenburg et al. 2011, ApJ 734, 9) we determined the magnetic helicity, 

along with the magnetic energy, at high latitudes using data from the Ulysses mission. The data 

set spans the time period from 1993 to 1996. The basic assumption of the analysis is that the solar 

wind is homogeneous. Because the solar wind speed is high, we follow the approach first pioneered 

by Matthaeus et al. (1982, PRL 48, 1256) by which, under the assumption of spatial homogeneity, 

one can use Fourier transforms of the magnetic field time series to construct one-dimensional spectra 

of the magnetic energy and magnetic helicity under the assumption that the Taylor frozen-in-flow 

hypothesis is valid. Our results show a sign change of magnetic helicity at wavenumber k ≈ 2 AU −1 

(or frequency ν ≈ 2 µHz) at distances below 2.8 AU and at k ≈ 30 AU −1 (or ν ≈ 25 µHz) at larger 

distances. At small scales the magnetic helicity is positive at northern heliographic latitudes and 

negative at southern latitudes. The positive magnetic helicity at small scales is argued to be the 

result of turbulent diffusion reversing the sign relative to what is seen at small scales at the solar 

surface. Furthermore, the magnetic helicity declines toward solar minimum in 1996. The magnetic 

helicity flux integrated separately over one hemisphere amounts to about 10 45 Mx 2 /cycle at large


scales and to a 3 times lower value at smaller scales. These results are discussed in the context of 

similar findings from simulations of dynamo-driven plasmoid ejections above a spherical surface by 

Warnecke et al. (arXiv:1104.0664). 

Multitude of scales in distribution of helicity of solar 

magnetic fields over the magnetic cycle 

K.M. Kuzanyan 1,2 , Yu Gao 2 and H. Zhang 2 

1 IZMIRAN, Russian Academy of Sciences, Troitsk, Moscow region, 142190 Russia 

2 Key Laboratory of Solar Activity, National Astronomical Observatories, 

Chinese Academy of Sciences, Beijing 100012, China 


Helicity is an important ingredient of the solar dynamo which, as measure of inhomogeneity of 

turbulence in rotating convective media, can twist and fold magnetic field lines, therefore, providing 

re-generation of the solar magnetic cycle. 

Systematic studies of current helicity and twist of solar magnetic fields in active regions reveal 

large-scale in latitude and time pattern which regularly varies in accord with the solar cycle. Earlier 

studies have shown that the sign of these helical quantities is specific to a given hemisphere (negative 

in the northern and positive in southern) with precision of a few isolated islands in latitude and time, 

in the middle of the wing of the butterfly diagram and only at the beginning and the end of each 

solar cycle, where the sign is systematically inverted. 

Helicity of solar active regions is a highly fluctuating quantity, both in space and time. Given 

long-term systematic database of helicity obtained at Huairou Solar Observing Station in China 

(1988-2005) we studied general trends of variability of helicity distribution over the scale of the solar 

cycle. For each two year time span we considered hemispheric distribution of helicity, comparing 

the average values with the etalon Gaussian distribution. We speculate on the nature of helicity in 

some active regions those are far from Gaussian means. Their latitudinal distribution and dynamics 

visualized over butterfly diagrams is similar to the one for the overall helicity. Therefore, we may 

expect that helicity in such off-mean active regions is likely produced by the same mechanism of 

solar activity but reflect different parts of the spectrum of solar turbulence. More detailed systematic 

observations of the Sun are required to establish the power spectrum of the helicity. 

Are the magnetic fields in the solar internetwork 

horizontal or isotropic ? 

J.M. Borrero 1 

1 Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany 


Investigations of the distribution of the magnetic field on the solar surface are key to understand 

the underlying small-scale magneto-convective processes that take place on the sun. In addition, 

the center-to-limb variation of the distribution of magnetic fields can also help us understand global 

processes such as meridional flow, torsional oscillations and their relation to the solar cycle. Nowadays, 

there is no consensus as to whether the distribution of the magnetic fields in the internetwork is 

isotropic or it contains mostly horizontal fields. 

In this contribution we study the center-to-limb variation of the polarization profiles in the internetwork 

employing high signal-to-noise data from Hinode/SP. Spectropolarimetric inversions to 

retrieve the magnetic field vector at different µ-angles are inconclusive because of the effect that the


photon noise has in the retrieval of the horizontal component of the magnetic field. However, the 

histograms of the observed Stokes profiles demonstrates that the distribution of the magnetic field 

cannot be isotropic, as it changes significantly with the heliocentric angle: the number of profiles with 

linear polarization signals above the noise, decreases towards the limb. We confirm this by means 

of Monte Carlo simulations employing different theoretical distributions for the magnetic field in the 

internetwork. The best fit to the observed distribution of profiles is obtained with a theoretical distribution 

where the horizontal component of the magnetic field is, on average, 2-3 times stronger than 

the vertical component of the magnetic field. This ratio decreases towards the limb, which allows 

us to explain the smaller number of linear polarization profiles above the noise at larger heliocentric 

angles. 

Supersonic horizontal flows in the solar granulation 

L.R. Bellot Rubio 1 

1 Instituto de Astrofísica de Andalucía, Granada, Spain 


Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering 

3%-4% of the solar surface at any time, but these flows have not been detected unambiguously as 

yet. Using data from the spectropolarimeter aboard the Hinode satellite, I present direct evidence 

of fast horizontal plasma motions in quiet-Sun granules. Their visibility increases toward the limb 

due to more favorable viewing conditions. At the resolution of Hinode, the horizontal flows give 

rise to asymmetric intensity profiles with very inclined blue wings and even line satellites located 

blueward of the main absorption feature. Doppler shifts of up to 9 km s −1 are observed at the edges 

of bright granules, demonstrating that the flows reach supersonic speeds. The strongest velocities 

occur in patches of 0farcs5 or less. They tend to be associated with enhanced continuum intensities, 

line widths, and equivalent widths, but large values of these parameters do not necessarily imply 

the existence of supersonic flows. Time series of spectropolarimetric measurements in regions away 

from the disk center show the transient nature of the strong horizontal motions, which last only for 

a fraction of the granule lifetime. Supersonic flows are expected to produce shocks at the boundaries 

between granules and intergranular lanes, and may also play a role in the emergence of small-scale 

magnetic fields in quiet-Sun internetwork regions.


Session 4 

Emergence and Evolution of Magnetic Flux in the Solar 

Atmosphere


.


Magnetic flux emergence: a precursor of solar dynamic 

phenomena. 


V. Archontis 1 

1 University of St. Andrews, Mathematical Institute 


We present numerical experiments and observations that shed new light on the dynamical emergence 

of magnetic fields from the solar interior to the corona. We describe the response of the 

highly stratified solar atmosphere on flux emergence and we introduce a comprehensive picture of the 

coupling between solar dynamic phenomena and the emergence of magnetic flux. 

New Insights into the Origin and Evolution of Coronal 

Mass Ejections 

I. I. Roussev 1 , K. Galsgaard 2 , C. Jacobs 3 and N. Lugaz 1 

1 Institute for Astronomy, 2680 Woodlawn Drive, Honolulu, HI 96822, USA 

2 Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark 

3 Katholieke Universiteit Leuven, Centrum voor Plasma Astrofysica, Celestijnenlaan 200B bus 2400, 

3001 Leuven, Belgium 


The physical causes leading to the occurrence of Coronal Mass Ejections (CMEs) on the Sun 

have been debated for almost four decades now. One of the leading mechanisms suggests that a 

CME may occur as the result of the emergence of a twisted magnetic flux rope from the convection 

zone into the solar corona. This process has been investigated by a number of researchers over the 

years, and it has been demonstrated that an eruption of the coronal magnetic field can in principle 

occur. The majority of these studies, however, involve some ad-hoc prescription of the electric field 

at the photosphere resembling flux emergence, and they neglect the ambient coronal magnetic field. 

In addition, most of these flux-emergence simulations are performed in a Cartesian domain, which 

extends only to a few dozen pressure scale-heights into the corona. Thus, it is difficult to assess 

the role of boundary driving and limited computational domain on the resulting evolution of the 

erupting coronal magnetic field. In this paper, we present a new model of CMEs that mitigates 

these two effects. To achieve this, we couple the “local” magnetic-flux-emergence (MFE) model of 

Archontis et al. (2004) with a global MHD model of the solar corona and solar wind. The model 

coupling is performed using the Space Weather Modeling Framework. In the coupled model, the 

MFE simulation provides time-dependent boundary conditions for all MHD quantities into the global 

model, where the physical coupling is done at the photospheric boundary. The physical evolution of 

the system is followed using the BATS-R-US “ideal” MHD code well beyond the complete emergence 

of the magnetic flux from the convection zone. We discuss the dynamics of the flux emergence process 

and the related response of the pre-existing coronal magnetic field in the context of CME production.


Are chromospheric swirls channeling energy from the 

photosphere into the corona? 

S. Wedemeyer-Bohm 1 

1 Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo, Norway 


Recently discovered chromospheric swirl events may channel energy from the photosphere into 

the corona and may contribute significantly to the heating of the upper solar atmosphere in quiet 

Sun regions. Swirls were first detected in intensity maps obtained in the core of the Ca II line 

at 854.2 nm. They appear as Doppler-shifted thin ring fragments with diameters on the order of 

2 arcsec above compact groups of photospheric bright points. The swirling motion is most likely 

caused by the twisting and braiding of the magnetic field at small spatial scales which results from 

the differential movement of magnetic footpoints due to convective buffeting in the low photosphere. 

Although, despite that swirls are abundant in the quiet Sun regions it is challenging to observe them. 

Consequently, their implications for the heating of the upper atmosphere have been elusive until now. 

New three-dimensional radiation magnetohydrodynamic simulations allow for an in-depth investigation 

of swirl events. In these simulations, which extend from the convection zone into the upper 

chromosphere, swirls develop automatically from an initially weak magnetic field. They appear in 

abundance as an integral part of the simulated atmosphere. I will present the results of these computationally 

involved simulations and support my findings with comparing corresponding synthetic 

Ca intensity maps with recent observations obtained with the CRISP instrument at the Swedish 

Solar Telescope at high spatial, temporal, and spectral resolution. The in-depth analysis of this 

class of small-scale events shows that they are potentially very important building blocks of the solar 

atmosphere, particularly in view of the heating of the upper solar atmosphere. 

Observational Investigations of Magnetic Fields and Their 

Emergence in the Solar Atmosphere 


A. Asensio Ramos 1 

1 Instituto de Astrofísica de Canarias, 38205, La Laguna, Tenerife, Spain 


The emergence of magnetic flux in the solar atmosphere produces perturbations on the plasma that 

are widely known. I show how the properties of the magnetic field at photospheric and chromospheric 

heights on these regions can be investigated through the analysis of the Zeeman and Hanle effects. In 

this talk I show that, even though the magnetic flux emergence occurs at many scales, its appearance 

is amazingly similar across scales.


High-resolution observations of small-scale magnetic flux 

emergence at the photosphere and response of the upper 

atmospheric layers 

S.L. Guglielmino 1 , V. Martínez Pillet 1 , J.C. del Toro Iniesta 2 , 

L.R. Bellot Rubio 2 , F. Zuccarello 3 et al. 

1 Instituto de Astrofísica de Canarias, C/ Vía Láctea s/n, La Laguna, Tenerife, E-38200, Spain 

2 Instituto de Astrofísica de Andalucía (CSIC), Apdo. de Correos 3004, E 18080 Granada, Spain 

3 Dipartimento di Fisica e Astronomia, Università di Catania, Via S. Sofia 78, 95123 Catania, Italy 


We present extremely high-resolution observations of flux emergence events at arcseconds scale 

acquired by IMaX during the first science flight of the SUNRISE balloon-borne solar telescope in 2009 

and by Hinode/SST during a joint observational campaign in 2007. The advances in observational 

capabilities allow us to investigate the evolution of emerging flux concentrations in the photosphere 

with a spatial resolution of about 0.2 ′′ . 

IMaX high-temporal cadence data shows the emergence of a bipole at granular scale (flux content 

∼ 10 18 Mx), that fades with time as a result of a decay process and of the coalescence with pre-existing 

flux elements. Other IMaX observations show the emergence of complex multi-polar structures with 

weak magnetic fields expanding over several granules, covering about 5 ′′ × 5 ′′ . 

The Hinode/SST deal with the emergence of an ephemeral region (flux content ∼ 10 19 Mx) 

appeared within a well-developed active region. These multi-wavelength simultaneous observations 

cover all the solar atmospheric layers, from the photosphere to the corona, and provide information 

about the higher atmospheric layers involved by the emergence process and about the interactions 

with the ambient field. We found that the reconnection between the emerging structure and the 

pre-existing coronal field gave rise to brightenings at several wavelengths and to a chromospheric 

surge. 

Our findings may provide useful constraints to the modelling of emerging flux regions. 

On the shapes of Stokes V profiles emerging in the 

quiet Sun 

B. Viticchié 1 , D. Mueller 1 , J. Sánchez Almeida 2 , N. Vitas 3 

1 ESA/ESTEC RSSD, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands 

2 Instituto de Astrofísica de Canarias, C/ Vía Láctea, s/n E38205, La Laguna (Tenerife), Spain 

3 SRON, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands 


The Stokes profiles emerging from the solar photosphere provide the most powerful tool to investigate 

the structure of the solar photosphere. More in detail, Stokes V asymmetries allow one to 

conclude on the stratification of both the magnetic field and plasma velocity along the line-of-sight. 

We present the results of two different analyses performed on HINODE SOT/SP data in the 

last year with the aim of pointing out the significance of Stokes V asymmetries in the quiet Sun 

and, as a direct consequence, the need of more refined analyses of high spatial resolution polarization 

measurements (e.g., from SOT/SP and IMaX). Besides this, we report on a recent analysis of Stokes 

profiles emerging from quiet Sun MURaM snapshots aimed at obtaining hints on the formation of 

one specific category of extremely asymmetric profiles, namely, single-lobed profiles.


Solar pore: relations between magnetic and velocity fields 

M. Sobotka 1 , D. Del Moro 2 , J. Jurčák 1 , M. Vantaggiato 2 and F. Berrilli 2 

1 Astronomical Institute, Academy of Sciences of the Czech Republic, Fričova 298, 25165 Ondˇrejov, Czech Republic 

2 Department of Physics, University of Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma, Italy 


Solar pores, “naked umbrae”, offer an unique opportunity to study the interaction between magnetic 

field, Doppler (LOS) velocity, and horizontal motions. A large pore with a light bridge was 

observed with the IBIS spectrometer attached to the Dunn Solar Telescope. Full-Stokes profiles of 

the line Fe I 617.3 nm were reconstructed from series of narrow-band images and inverted into a timeseries 

of maps of temperature, magnetic field components, and LOS velocity. Simultaneous maps of 

horizontal motions were obtained from white-light images using the local correlation tracking. 

We describe relations between magnetic field components and temperature, LOS velocity, and 

horizontal motions in the pore and in its surroundings. Magnetic field extends far beyond the pore’s 

edge. The magnetic radius of the pore is by factor 1.75 larger than its visible radius. We found that 

the temperature linearly decreases with increasing vertical magnetic field component. The rate of 

decrease is lowest in photospheric granulation and highest in the umbra. The temperature pattern 

of granulation is suppressed by vertical field higher than 1000 G. The LOS velocity signature of 

granulation disappears in magnetic field higher than 900–1000 G. Granular upflows dominate in 

regions where the vertical field is below 500 G. A ring of divergence centres of horizontal granular 

motions (sites of recurrently exploding granules) surrounds the pore at a distance where the extended, 

mostly horizontal magnetic field is equal to 400 G. These findings can be used as constraints for MHD 

simulations of solar pores. 

The sunspot moat flow as seen with HMI/SDO 

Johannes Löhner-Böttcher and Rolf Schlichenmaier 

Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany 


In order to model the subsurface structure of sunspots it is certainly crucial to understand the 

sunspot moat flow, which always surrounds fully-fledged sunspots. However, although the moat flow 

is known since about 40 years, it has not yet been studied systematically. The full disk Dopplermaps 

of HMI/SDO at a spatial resolution of 1 arcsec make it now possible to study the moat flow properties 

for large samples of sunspots, which can be compared with the outcome of numerical models. 

In this contribution we characterize the sunspot moat flows using Dopplermaps in Fe I 617.3 nm 

from HMI/SDO. In order to yield reliable values for the line-of-sight velocities, we carefully calibrate 

the Dopplermaps: We determine the radially symmetric center-to-limb variation of the convective 

blueshift. After taking care of the differential rotation and the inclination of the solar rotation axis, a 

fringe pattern with a variation of ±200 m/s across the field-of-view remains. From COBOLD models 

of the quiet Sun we determine the convective blue shift at disk center to be -300 m/s (courtesy: H.-G. 

Ludwig). 

We selected a sample of stable roundish sunspots (i.e., of theoretician type). The spots are at 

heliocentric angles larger than 45 ◦ to retrieve a large fraction of the horizontal component of the moat 

flow. We find that the horizontal velocity component of the moat flow decreases monotonically from 

an average value of 800 m/s at the outer spot boundary. Interestingly, small spots have larger moat 

flow velocities than large spots. We will present more statistical properties of the moat flow and will 

discuss those properties in the context of moat flow models.


Flocculent flows in superpenumbral fibrils: a new view 

on the inverse Evershed effect? 

G.J.M. Vissers 1 and L.H.M. Rouppe van der Voort 1 

1 Institute of Theoretical Astrophysics, University of Oslo 


Since its discovery over a century ago, the inverse Evershed effect (the inward directed flow 

observed in the superpenumbra of sunspots) has been studied extensively. However, different ranges in 

velocities have been reported in spectroscopic and filtrographic studies and also its driving mechanism 

remains a matter of debate. Recently, high spatial, temporal and spectral resolution observations 

were obtained in the Hα line (6563 ˚A) with the CRisp Imaging SpectroPolarimeter (CRISP) at the 

Swedish 1-m Solar Telescope (SST), covering a small sunspot with a rudimentary penumbra and some 

plage. These observations show the superpenumbra exhibiting ubiquitous inward flows with a clearly 

flocculent character that is morphologically reminiscent of coronal rain. 

We perform a statistical analysis to derive properties such as velocities, accelerations and sizes of 

the dark flocculent features in these fibrils. Both the location of the flows and comparison of their 

properties with those obtained previously for the inverse Evershed effect suggest the flocculent flows 

constitute at least a component of that inverse flow, but are driven by a different mechanism than 

the regular Evershed effect. In that context, we discuss catastrophic cooling leading to downflowing 

condensations (i.e., the commonly accepted mechanism driving coronal rain), (episodic) siphon 

flows and waves propagating along the superpenumbral fibrils as possible driving mechanisms of the 

observed phenomenon. 

Dynamo-driven plasmoid ejections above a spherical surface 

J. Warnecke 1,2 , A. Brandenburg 1,2 and D. Mitra 1 

1 Nordita, AlbaNova University Center, Roslagstullsbacken 23,SE-10691 Stockholm, Sweden 

2 Department of Astronomy, AlbaNova University Center, Stockholm University, SE-10691 Stockholm, Sweden 


Observations show that the Sun sheds mass through twisted magnetic flux configurations, like 

Coronal Mass Ejections (CMEs). Conventionally, CMEs are modeled by adopting a given distribution 

of magnetic flux at the solar surface and letting it evolve by shearing and twisting the magnetic field 

at its footpoints at the surface. Of course, ultimately such velocity and magnetic field patterns must 

come from a realistic simulation of the Sun’s convection zone, where the field is generated by dynamo 

action. Therefore a unified treatment of convection zone and CMEs is needed. We extend earlier 

models of turbulent dynamos with an upper, nearly force-free exterior to spherical geometry, and 

study how flux emerges from the lower layers to the upper ones without being driven by magnetic 

buoyancy. We also study how this affects the possibility of plasmoid ejection. A spherical wedge 

is used that includes northern and southern hemispheres up to mid-latitudes and a certain range 

in longitude of the sphere. In radius, we cover both the region that corresponds to the convection 

zone in the Sun and the immediate exterior up to twice the radius of the Sun. Turbulence is driven 

with a helical forcing function in the interior, where the sign changes at the equator between the two 

hemispheres. An oscillatory large-scale dynamo with equatorward migration is found to operate in 

the turbulence zone. Plasmoid ejections occur in regular intervals, similar to what is seen in earlier 

Cartesian models. These plasmoid ejections are tentatively associated with Coronal Mass Ejections 

(CMEs). The magnetic helicity is found to change sign outside the turbulence zone, which is in 

agreement with recent findings for the solar wind.


.


Session 5 

Chromospheric and Coronal Heating


.


A Progress Report on Coronal Heating 


J.A. Klimchuk 1 

1 NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA 


The past three years have seen a number of exciting developments in understanding coronal (and 

chromospheric) heating, including some very recent results from the Solar Dynamics Observatory. I 

will offer a progress report on the efforts to solve this fundamental problem, including an assessment 

of where we stand and where we need to go. 

3D Simulations of Wave Heating; where is all the energy? 

I. De Moortel 1 and D.J. Pascoe 1 

1 School of Mathematics & Statistics, University of St Andrews, North Haugh, St Andrews, KY16 9SS, UK 


Recently, observations have shown that transverse oscillations are present in a multitude of coronal 

structures. It is generally assumed these oscillations are driven by (sub)surface footpoint motions. 

Using fully 3D MHD simulations, we show that these footpoint perturbations generate propagating 

kink modes which couple very efficiently into Alfvén waves. We investigate the energy budget contained 

within such oscillations in various different ways. We compare the footpoint energy with the 

energy budget at higher altitudes and show the distribution of the temperature resulting from the 

phasemixing of the Alfvén waves. Using an ensemble of randomly distributed loops, driven by footpoint 

motions with random periods and amplitudes, we compare the absolute energy in the numerical 

domain with the energy that is ’visible’ when integrating along the line of sight. We show that this 

’LOS energy’ is only a small fraction of the actual energy provided by the footpoint motions. 

Scale invariant coronal heating by (nano-)flares in 

a 3D MHD model 

S. Bingert 1 , H. Peter 1 

1 Max Planck Institute for Solar System Research; Max-Planck-Str. 2; 37191 Katlenburg-Lindau Germany 


We present 3D MHD models of the solar coronae revealing an energy input by Ohmic heating 

that is highly intermittent in space and time. This sheds new light on the long-standing debate of 

constant vs. transient heating, and reconciles these two views. 

In these models the dynamics and the structure of the corona is a result of the driving by the 

photospheric motions and the self-consistent treatment of the heating by braiding the magnetic field 

lines and the Ohmic dissipation. 

We find that the heating is highly intermittent in space and time. On the one hand the heating is 

distributed along magnetic field lines which results in a hot and dense coronal loop on the other hand 

the current sheet like structures are composed of short lived heating events. We analyze the temporal 

and spatial distribution using a frequency distribution. Latter corresponds to a power law with a 

slope comparable to observational data. We show the resulting slopes of the frequency distributions


and discuss weather the heating is dominate by small events (nanoflares) or large events depending 

on the atmospheric layer (chromosphere,transition region, and corona). 

As the intermittent heating produces a stable coronal loop system with a minor temporal variation 

we derive scaling laws and compare those with the well known scaling laws based upon steady heating. 

This aims at the discussion weather impulsive heating or steady heating is dominant and responsible 

to form the hot coronal loops. 

Signatures of Impulsive Coronal Heating in Warm and 

Hot Spectral Lines 

S. Patsourakos 1 , J. A. Klimchuk 2 and P.R. Young 3 

1 University of Ioannina,Dept Physics-Section Astrogeophysics, GR 45110 Ioannina, Greece 

2 NASA Goddard Space Flight Center, Solar Physics Lab, Code 671 Greenbelt, MD 20771, USA 

3 George Mason University, 4400 University Drive, Fairfax, VA 22030, USA 


Impulsive coronal heating predicts faint, yet measurable, amounts of plasmas at very high temperatures 

exceeding few MK, making up a small fraction of the plasma residing at warmer coronal 

temperatures (1-2 MK). Moreover, the spectra of hot lines can exhibit asymmetries under impulsive 

heating conditions. Such asymmetries are the signature of the fast evaporating plasma during heating 

events. It is therefore obvious that analyzing hot spectral lines is a rather challenging (due to their 

intrinsic weakness and the potential interference from line blends) but yet particularly rewarding 

problem. Using specially-designed sequences of the EIS spectrometer on-board HINODE we will 

report on: (1) the emission measure ratio between warm and hot plasmas as a function of location 

and time within active regions and (2) potential signatures of line asymmetry in the profiles of hot 

spectral lines. We will also address in detail the expected line shapes from impulsive heating in warm 

spectral lines and discuss whether they can explain the recent observations of asymmetries in warm 

lines. 

Cool loops contribution to the transition region EUV output 

C. Sasso 1 , V. Andretta 1 and D. Spadaro 2 

1 INAF - Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy 

2 INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy 


In the last 30 years, the existence of small and cool magnetic loops has been proposed and 

debated to explain the increase of the DEM (differential emisson measure) towards the chromosphere. 

The general properties of quasi-static cool loops and the conditions of stability and existence were 

first studied theoretically by Antiochos & Noci (1986) and both analytically and numerically by 

Cally & Robb (1991). This class of loops shows specific characteristics; cool loops are low-lying 

(estimates heights 1.1-5 Mm), nearly isobaric, and with maximum temperature below 10 5 K. Contrary 

to the classical coronal loops, the conductive flux plays a negligible role and static cool loops are in 

approximate balance between the heating rate and radiative losses. 

In this work we show that stable, quasi-static cool loops (with velocities < 1 km/s) can be 

obtained through hydrodynamic simulations, also under different and more realistic assumptions on 

the radiative losses function with respect to the work of Cally & Robb (1991). In particular, we 

obtain static cool loops like those predicted by Antiochos & Noci (1986), even for a set of parameters 

that would prevent the formation of rigorously static loops. We have also obtained and studied loops 

with ”intermediate” temperatures, between 10 5 and 10 6 K. 

After a preliminary analysis, we show that a mixture of ”cool” and ”intermediate” loops can 

reproduce the observed emission of the lower transition region at the critical turn-up temperature 

point (T∼ 2 × 10 5 K) and below T= 10 5 K.


What can we learn about coronal heating from spicules? 


B. De Pontieu 1 

1 Lockheed Martin Solar & Astrophysics Laboratory, Palo Alto, CA, USA 


The Sun’s corona is heated to millions of degrees, considerably hotter than the photosphere. 

Explanations for this long-standing enigma typically invoke the deposition in the corona of nonthermal 

energy generated by the interplay of convection and magnetic fields. However, the exact 

physical mechanism driving coronal heating remains unknown. During the past few years, recently 

built instruments like the Japanese Hinode satellite, the Swedish Solar Telescope in Spain and NASA’s 

Solar Dynamics Observatory (SDO) combined with advanced numerical simulations have revealed a 

new window into how the Sun’s atmosphere is energized. I will describe some of these results, 

and present observational evidence of heating of plasma to coronal temperatures in association with 

chromospheric spicules, jets of plasma that are propelled at speeds of order 50-100 km/s. I will also 

show evidence for pervasive Alfvén waves in the transition region and corona, with an energy flux 

density of order 100-200 W/m 2 , which is in principle enough to play a significant role in the energy 

balance of the corona and solar wind. 

Mass Transport in the Solar Atmosphere. 

N. Guerreiro 1 and V. Hansteen 1 



Observations of transition region emission lines reveal the presence of redshifts in lines formed from 

the top of the chromosphere up to temperatures of about 250000 K and blueshifts for temperatures 

above that. However, it is doubtful that the apparent large downward flows in the lower transition 

region represent an emptying of the corona, so some mechanism must be responsible for maintaining 

the mass balance between the lower atmospheric layers and the corona. We use a 3D-MHD code, 

Bifrost, which includes non-LTE radiative transfer in the photosphere and lower corona, optically 

and effectively thin radiation in the upper chromosphere, transition region and corona, conduction 

along the magnetic field lines and heating through the ohmic dissipation of tangled magnetic field 

lines to simulate the solar atmosphere. The motion of material originally in the transition region is 

tracked. We report on the coronal mass balance and the mass flow mechanism for conditions typical 

of the quiet sun. 

Ejection of cool plasma into the hot corona 

P. Zacharias 1 , S. Bingert 2 and H. Peter 2 

1 International Space Science Institute, Bern, Switzerland 

2 Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany 


We are applying three-dimensional magnetohydrodynamic (3D MHD) models extending from the 

photosphere to the corona above a small active region to investigate mass flows in the upper solar 

atmosphere. These models account properly for the energy balance, especially for heat conduction


and radiative losses, allowing us to reliably synthesize the profiles of optically thin EUV emission 

lines 

Processes leading to the formation and subsequent ejection of cool plasma into the corona are 

discussed, and a detailed description of the nature of this particular phenomenon is provided. The 

analysis of the various forces acting upon the plasma shows that the pressure gradient driving the 

ejection is due to the Ohmic dissipation of currents resulting from the braiding of the magnetic field 

lines by photospheric plasma motions. 

In the second part, we focus on the origin of Doppler shifts in the MHD model. The presence of 

upflows at low temperatures suggests the existence of cool pockets of plasma that are pushed upwards 

from below supplying mass into the corona, where the plasma is heated and then rains down. These 

pockets heat up slowly as they rise which means that they are not observable as blueshifts in the 

transition region and coronal lines. The investigation of the magnetic field topology shows magnetic 

field lines that are intermittently connected to subjacent regions of either strong or weak heating 

leading to either plasma being accelerated upwards along the field line (observed as a blueshift) or 

material flowing back down along the field line (observed as redshifts). Future investigations will 

have to confirm if such a chromosphere-corona mass cycle is a ubiquitous process on the Sun. 

Helicity in spicules and explosive events 

W. Curdt 1 and H. Tian 2 


2 High-Altitude-Observatory, NCAR, Boulder, 80301 Co., USA 


Since decades people wonder why the spectroscopic motion of explosive events that is easily seen 

as Doppler flow in transition region lines, does not spawn detectable apparent motion. The awareness 

of this discrepancy led us to the alternate interpretation of redshift and blueshift as spinning motion 

of a small volume of plasma. We report two observations of textbook double-component explosive 

events, that are extreme cases of Doppler flow that lacks apparent motion and that can hardly be 

interpreted as a pair of collimated, linearly moving jets, while the concept of a small volume of 

spinning plasma in a spicule would be fully compatible with the observations and could explain the 

lack of apparent motion. We argue that the observed helical motion in macrospicules can be scaled 

down to arcsecond-size features and discuss the spectroscopic signature and consequences of such 

a scenario. We now believe that explosive events and spicules are different manifestations of the 

same helicity driven scenario. The insight that explosive events might be nothing else than spinning 

spicule-like structures that imagers observe as spicules and that in spectrometers cross the slit and 

are seen as explosive events is hardly compatible with the concept of a reconnection event in the 

transition region. 

A rainy day on the Sun 

P. Antolin 1,2 , L. Rouppe van der Voort 1,2 and E. Verwichte 3 

1 Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo, Norway 

2 Center of Mathematics for Applications, University of Oslo, P.O. Box 1053, Blindern, NO-0316, Oslo, Norway 

3 Department of Physics, University of Warwick, Coventry CV4 7AL, UK 


Observed in cool chromospheric lines such as Hα or Ca ii H, coronal rain corresponds to cool 

and dense plasma falling from coronal heights. Considered rather as a peculiar sporadic phenomenon 

of active regions, it has not received much attention since its discovery more than 40 years ago. 

Yet, it has been shown recently that a close relationship exists between this phenomenon and the


coronal heating mechanism. Indeed, numerical simulations have shown that this phenomenon is most 

likely due to a loss of thermal equilibrium ensuing from a heating mechanism acting mostly towards 

the footpoints of loops. In this work we show the important role it can play in the understanding 

of the coronal magnetic field. We start by presenting Hinode/SOT observations in the Ca ii H 

line where in-phase transverse oscillations of multiple strand-like structures in a loop are put in 

evidence by coronal rain. Estimates of the coronal magnetic field and the energy flux of the waves are 

given through helioseismology techniques. We then present the first multi-wavelength high resolution 

spectroscopic observations of coronal rain, performed by the CRISP instrument at the Swedish Solar 

Telescope. The condensations composing coronal rain are observed to elongate and separate as they 

fall down to sizes as small as the diffraction limit resolution of the SST. At this resolution, coronal 

rain is observed to literally invade the entire field of view, implying that coronal rain may be a 

common phenomenon, and thus that thermal non-equilibrium is important for coronal heating. A 

large statistical set is obtained in which temperatures and dynamics of the condensations are derived. 

Simultaneous observations obtained with SDO provides a complementary picture of the ambient 

corona, thus allowing further insight into the local and global physical conditions. 

Partial ionization effects in the solar photosphere and 

chromosphere 

E. Khomenko 1,2 and M. Collados 1,2 

1 Instituto de Astrofísica de Canarias, 38205 La Laguna, Spain 

2 Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Spain 


The particular temperature and density conditions in the magnetized photosphere and chromosphere 

of the Sun can lead to a very small degree of atomic ionization. In addition, the magnetic field 

may be strong enough to give rise to a cyclotron frequency larger than the collisional frequency for 

some species, while for others the opposite may happen. Under these circumstances, the collective 

behavior of the particles may be influenced and some of the hypotheses of magnetohydrodynamics 

may be relaxed, giving rise to additional terms in the classical MHD equations. In this contribution, 

the results of numerical simulations using the modified equations applied to magnetic structures of 

diverse field strength will be shown. Some consequences derived from the new terms of the equations 

on the solar photosphere and chromosphere will be discussed. 

Realistic simulations of the impact of partial ionization 

on the chromosphere 

J. Martínez-Sykora 1,2 , B. De Pontieu 2 and V. H. Hansteen 1 

1 Institute of theoretical astrophysics, University of Oslo 

2 Lockheed Martin Solar and Astrophysics Lab 


We investigate the importance and consequences of introducing the effects of neutral particles into 

the MHD equations in 3D advanced radiative MHD simulations obtained from the Bifrost code. We 

use a model that spans the upper layer of the convection zone to the low corona. The chromosphere is 

partially ionized and the interaction between ionized and neutral particles has important consequences 

on the thermodynamics of this region. We implemented the effects of partial ionization using the 

generalized Ohm’s law, i.e., we consider the effects of the Hall and ambipolar diffusion in the induction 

equation. We have tested the various approximations that are involved in using the generalized Ohm’s 

law (instead of a multi-fluid approach) using 2.5 D simulations, and find that that the assumptions 

behind the generalized Ohm’s law are not always satisfied in the upper-chromosphere and in the 

transition region.


Wave propagation in the solar atmosphere: explaining 

observations with a simple model 

M. Stangalini 1 , D. Del Moro 1 , F. Berrilli 1 , S. M. Jefferies 2 

1 Università di Roma Tor Vergata 

2 Institute for Astronomy - University of Hawai’i 


MHD waves propagation inside the Sun’s atmosphere has been extensively found to be related to 

the magnetic field topology. Magnetic fields are in fact able to lower the cutoff frequency and then to 

allow the propagation of low frequency waves (< 5mHz) toward the upper atmosphere. In addition 

to this, at altitudes where the sound speed equals the Alfvén speed, MHD waves can be transmitted 

or converted into other forms of waves. Taking advantage of the large bidimensional field of view 

provided by IBIS, we study the wave propagation at two heights sampled by the photospheric Fe 617.3 

nm spectral line, and the chromospheric Ca 854.2 nm spectral line with respect to the field inclination. 

By using spectropolarimetric inversions of Hinode SOT/SP data, we put in relation the photospheric 

power spectrum with the estimated magnetic field inclination angle, finding a transmission peak 

around 25 degrees for 5 minutes waves and around 15 degrees for 3 minutes waves. We propose 

a very simple model to explain the observed behavior, based upon wave transmission theory. By 

analyzing both power spectra and chromospheric amplification spectra we also found hints for the 

presence of longitudinal acoustic waves along the field lines. 

The temperature structure of the solar chromosphere 

J. Leenaarts 1 

1 Sterrekundig Instituut, Utrecht University, Postbus 80 000 NL–3508 TA Utrecht, The Netherlands 


I will present radiative MHD simulation of the solar atmosphere spanning from the upper convection 

zone into the lower corona. The simulation has an advanced equation-of-state, including 

non-equilibrium ionization of hydrogen and non-equilibrium H2 molecule chemistry. The simulated 

chromosphere is pervaded by propagating shock waves with a temperature of 10,000 K. In between 

these shocks the chromosphere can cool down to below 1500 K if there is no significant magnetic 

heating. 

In addition I will show a 3D NLTE radiative transfer computation of the Ca II H and 8542 

IR lines from an MHD snapshot containing a current sheet in the mid-chromosphere. This current 

sheet appears as a loop-like structure, but is in fact not aligned with the magnetic field lines. These 

computations can help in the interpretation of observations.


The Chromospheric Solar Sub-millimeter Cavity and the 

Minimum of Temperature 

V. De la Luz 12 , A. Lara 2 and Jean-Pierre Raulin 3 

1 Instituto Nacional de Astrofisica, Optica y Electronica, Mexico. 

2 Universidad Nacional Autonoma de Mexico, Instituto de Geofisica, Mexico. 

3 Centro de Radio Astronomia e Astrofisica, Universidad Mackenzie, Brazil. 


Observations in the visible from the line of emission of H and K of Caii, in the UV from the Mg 

h and k resonance lines, the 135-168 nm UV continuum and the 33-500 µm microwave continuum 

suggest a low temperature in the solar chromosphere. Several semi-empirical models set this minimum 

of temperature between 400 and 600 km over the photosphere. In this work, we show that there is an 

optical cavity originated by two major regions of emission at millimeter, sub-millimeter, and infrared 

regimes. Observations at these wavelengths seem to confirm the presence of this structure.


.


Session 6 

Transient Activity and Seismology of the Solar Atmosphere


.


New developments in coronal seismology 


T. Van Doorsselaere 1,2 

1 Centre for Plasma Astrophysics, Mathematics Department, K.U.Leuven,Celestijnenlaan 200B bus 2400, 

3001 Heverlee, Belgium 

2 Post-doctoral fellow of the FWO-Vlaanderen. 


In coronal seismology observed properties of coronal waves are compared to state-of-the-art models. 

The value of physical quantities is then estimated by the adjustment of the model parameters, 

so that the model matches the observed oscillation. Successful coronal seismology thus requires 

both detailed observations and the development of new observational techniques, as well as further 

development of MHD wave models. 

I will give an overview of new observational insights gained with modern instruments, including 

SDO/AIA. I will discuss the recently constructed models that attempt to explain the observed 

phenomena, and are used to gain seismological information on the solar coronal environment. 

Bayesian inversion technique for seismology of the solar 

atmosphere 

I. Arregui 1 and A. Asensio Ramos 2 

1 Departament de Física, Universitat Illes Balears, E-07122 Palma de Mallorca, Spain 

2 Instituto de Astrofísica de Canarias and Universidad de La Laguna, E-38205, Tenerife, Spain 


Seismology of the solar atmosphere aims to determine difficult to measure physical parameters in 

the solar corona by a combination of observed and theoretical properties of waves and oscillations. 

Current inversion techniques show a number of limitations, such as the obtention of different solutions 

that equally well reproduce observed wave properties. There is an additional need to devise inversion 

techniques that correctly propagate uncertainties from observations to inferred parameters. We show 

how the use of statistical techniques in combination with Markov chain Montecarlo simulations can 

help to overcome these limitations. An example is provided in which bayesian inference is applied to 

the determination of physical parameters in coronal loops, using their transverse oscillations. Our new 

approach enable us to infer the most probable values of the relevant parameters compatible with the 

observed wave properties, and to extract their confidence levels incorporating observed uncertainties 

in a consistent manner. The presented technique can be directly applied to other solar atmospheric 

structures that display wave dynamics. We believe it will be of high value for the near future of solar 

atmospheric seismology, when the inversion of physical parameters will be based on the combination 

of numerical parametric results and the analysis of large data sets obtained from observations.


Oscillations and Wave Propagation in the Solar Atmosphere 


E. Khomenko 1,2 

1 Instituto de Astrofísica de Canarias, 38205, C/ Vía Láctea, s/n, La Laguna, Tenerife, Spain 

2 Departamento de Astrofísica, Universidad de La Laguna, 38205, La Laguna, Tenerife, Spain 


The magnetized upper atmosphere of the Sun (photosphere, chromosphere and corona) has always 

been challenging for studies of the wave propagation, as different physical agents often come into play 

with almost equal weight, making arbitrary the division into pure wave modes and complicating 

theoretical models. Significant advances have been made recently in our understanding of the physics 

of waves in solar active regions with the help of analytical theories, numerical simulations, as well 

as hi-resolution observations. In this contribution, I will review the current ideas in a field that is 

becoming more and more relying on numerical simulations, putting emphasis on the most recent 

theoretical modeling of waves. I will discuss the following questions: (i) Interpretation of the waves 

observed in different magnetic structures in the upper atmosphere of the Sun in terms of MHD modes; 

(ii) Role of the mode transformation and observational evidences of this process; (iii) Contribution 

of the MHD wave energy for the heating of the upper atmosphere. 

The chromospheric magnetic field and the determination 

of the height of the magnetic canopy 

I. Kontogiannis 1,2 , G. Tsiropoula 1 and K. Tziotziou 1 

1 National Observatory of Athens, Institute for Space Applications and Remote Sensing, Lofos Koufos, 

15236 Palea Penteli, Greece 

2 Department of Astrophysics, Astronomy and Mechanics, Faculty of Physics, National and Kapodistrian 

University of Athens, GR 15784 Zografos, Greece 


The dynamics of the quiet solar chromosphere is mainly governed by the (local) magnetic field. 

Recent theoretical as well as observational studies have revealed its crucial role in the propagation 

and/or channeling of waves, from the photosphere, where they are generated, to the upper solar 

atmosphere. Also shown by several studies is the important role played in wave propagation by the 

so-called magnetic canopy, the layer where the magnetic and gas pressures become comparable (i.e. 

the plasma-β ∼ 1 ). This layer provides the boundary wherein waves are reflected and refracted and 

influences their mixing and conversion. Motivated by these studies, we extrapolate the photospheric 

magnetic field given by the SOT/SP onboard Hinode and by MDI onboard SoHO based on the 

current-free (potential) assumption which provides the minimum energy state of the chromospheric 

magnetic field. Furthermore, we calculate the plasma-β using several atmospheric models (e.g. VAL, 

FAL). We discuss the implications of using photospheric magnetic fields observed by instruments 

with different sensitivities and of different atmospheric models on the extrapolated chromoshperic 

magnetic field and the determination of the height of the magnetic canopy.


Three-minute oscillations above sunspot umbra observed 

with SDO and NoRH 

V.E. Reznikova 1 , K. Shibasaki 1 , R.A. Sych 2,3 , and V.M. Nakariakov 4,5 

1 Nobeyama Solar Radio Observatory, NAOJ, Japan 

2 National Astronomical Observatory (NAOC), Beijing, China 

3 Institute of solar-terrestrial physics, P.O.Box 4026, Irkutsk, Russia 

4 Physics Department, University of Warwick, Coventry, CV4 7AL, UK 

5 Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, 

196140 St Petersburg, Russia 


Three-minute oscillations over sunspot’s umbra in AR 11131 were observed simultaneously in radio 

emission by Nobeyama Radioheliograph (NoRH) and in UV/EUV emission by SDO/AIA. We use 

24-hour series of SDO and 8-hour series of NoRH observations. Fine spectral, spatial and temporal 

variations of the observed oscillations were analysed, the following features were found. 1) Fourier 

power spectra in the range 5-7 mHz have a clear fine structure with the dominant component changing 

with time. 2) Power of 3-min pulsations is modulated by longer period components: 6-7min, 10-12min. 

3) Modulation depth of radio and EUV 304 ˚A signals is about 20% on average and it decreases with 

height as it is seen in the hotter coronal emission lines 171˚A, 193˚A, and 211˚A. 4) Oscillations of 

higher frequency are more pronounced closer to the sunspot’s centre, in the umbra. The evolution 

of the 3-min oscillations and their spatial structure are discussed in terms of the possible time and 

spatial variation of the acoustic cut-off frequency, caused by variation of the minimum temperature 

in the sunspot’s umbra. 

Frequency drifts of three-minute oscillations in microwave 

and EUV above sunspots 

R.A. Sych 1 , T.V. Zaqarashvili 2 , V.M. Nakariakov 3 , S.A. Anfinogentov 4 , 

Y. Yan 1 and K. Shibasaki 5 


2 Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria 

3 University of Warwick, Coventry, UK 

4 Institute of Solar-Terrestrial Physics, P.O.Box 4026, Irkutsk, Russia 

5 Nobeyama Solar Radio Observatory, Minamisaku, Nagano, Japan 


We present the observations of oscillations in microwave and EUV emission above sunspots with 

use the datasets from the Nobeyama radioheliograph and the Solar Dynamic Observatory. It was 

found that the oscillations with periods 2-4 min appear in the form of repetitive trains of the duration 

8-20 min. The typical interval between trains is 30-50 min. The oscillation trains are transient in 

frequency and power. During the development of individual trains we detected a repetitive frequency 

drift of 3-min oscillations. Wavelet analysis showed three types of the frequency drift: positive, 

negative and without drift. The frequency changes coincide with the temporal dynamics of the train. 

The statistical study of the drifts shows that in the microwave band the negative frequency drifts 

dominate. Individual pulses of 3-min oscillations have an asymmetric shape in the form of repetitive 

shock waves. 

The comparative study of 3-min oscillations in the sequences of microwave and EUV images showed 

the appearance of fine spatial structures in the sunspot during the trains. These structures can be 

interpreted as waveguides that channel upward propagating slow magnetoacoustic waves, responsible 

for 3-min oscillations. A possible explanation of the observed frequency drift is the existence of two 

simultaneous factors: the first is related to the decaying nature of the original pulse that generates 

the wave; and the second is associated with the curvature of the waveguiding magnetic tubes and 

associated Doppler shift.


We suggest that sub-photospheric pulses propagating upwards in the stratified atmosphere can 

explain the observation. In the proposed scenario, the initial pulse quickly develops into a shock 

because of the decrease in the background density. The nonlinear wake behind the initial pulse oscillating 

with acoustic cut-off period (about 3-min in the solar chromosphere) leads to the consecutive 

shocks with the same period. The model calculations confirm the observation.


Session 7 

Solar Instabilities, Flares, and Coronal Mass Ejections


.


Particle Acceleration in Flares and CMEs 


K.-L. Klein 1 

Observatoire de Paris, LESIA-CNRS UMR 8109, F-92195 Meudon 


The Sun presents a unique opportunity to study particle acceleration in an astrophysical environment: 

remote sensing diagnostics of energetic particles (gamma rays, hard X-rays, radio waves) and 

of the coronal plasma environment where they are accelerated and radiate, as well as in situ measurements 

of particles that escape from the Sun (SEP=Solar Energetic Particles detected in space). 

Non-thermal particles are an important ingredient of solar energetic processes. Energetic particles 

in flares carry a significant fraction of the total energy released during the event, and SEP carry a 

large fraction of the energy of the associated CME. Energetic particles are also a key element of space 

weather. How and where particles are accelerated is hence a fundamental problem of solar eruptive 

processes. 

After a brief overview of observational signatures and acceleration processes, this talk will focus 

on the combined analysis of remote sensing and in situ observations. Evidence on acceleration regions 

and acceleration time scales will be presented. Open questions include the relationship between the 

acceleration of different particle species, and the relationship between radiating and escaping particles. 

Evidence for close connections exist, but quantitative analyses suggest also inconsistencies. The chain 

of processes through which particles proceed from the Sun to Earth is an important issue: acceleration 

in the corona, confinement within or escape from coronal magnetic structures, propagation through 

an interplanetary medium that is often different from simple models. In situ particle measurements 

from a closer vantage point than 1 AU are urgently required. They will show SEP populations that 

are less affected by interplanetary transport than at 1 AU and particle populations in the environment 

of shock waves in the inner heliosphere, with parameters different from those measured near Earth. 

Such observations will become possible with the Solar Orbiter and Solar Probe missions. 

SEP events and associated phenomena in the corona 

and IP space 

R. Miteva 1 , K.-L. Klein 1 , S. W. Samwel 2 , O. Malandraki 3 and G. Trottet 1 

1 Observatoire de Paris, LESIA, 5 place Jules Janssen, 92195 Meudon, France 

2 National Research Institute of Astronomy and Geophysics, Elmarsad st. PO box 11421, Helwan, Cairo, Egypt 

3 Institute of Astronomy and Astrophysics, National Observatory of Athens, 11810 Athens, Greece 


We present a comprehensive study of the characteristics of solar energetic particle (SEP) events 

and various phenomena of the active Sun. We selected all SEPs detected by GOES satellites from 

1996 to the present associated with X-class solar flares at western longitudes. Despite the preliminary 

restriction to well magnetically connected solar flares with similar X-ray emission strength, the associated 

SEP events have intensities (in proton flux units) covering several orders of magnitude. Here, 

we discuss this issue and the SEP−solar phenomena relationship primarily from an observational 

point of view. 

The main aim of the study is to identify those phenomena from the low solar corona up to interplanetary 

(IP) space that are temporally associated with SEP events observed at 1 AU. Namely, 

we study in detail the different emission signatures in the microwave (single-frequency data), metric 

(from radio spectral plots at decimeter to hectometer wavelengths) and in the X-ray range (GOES 

and partially with RHESSI). Additionally, each event is studied with respect to the kinematic characteristics 

of the associated coronal mass ejections and shock waves, the temporal profile of the observed 

in situ energetic electron fluxes and the dynamics of the IP magnetic field. Finally, we discuss the 

results in terms of different scenarios for particle acceleration and transport.


Instability of electrons trapped by coronal magnetic field 

and its evidence in a fine structure of solar radio spectra 

E.Ya. Zlotnik 

Institute of Applied Physics RAS, Nizhny Novgorod, Russia 


Solar radio emission is a significant source of information on coronal plasma parameters and 

processes occurring in the solar atmosphere. High resolution frequency, space and time observations 

together with the developed theory make it possible to retrieve the physical conditions in the radiation 

source and recognize the radiation mechanisms responsible for various kinds of solar radio emission. 

In particular, high brightness temperature of many bursts testifies to coherent radiation mechanisms, 

that is to plasma instabilities in the corona. 

As an example a fine structure of solar radio spectra looking as a set of quasi harmonic stripes 

of enhanced and lowered radiation which is observed against the type IV continuum at the post-flare 

phase of activity is considered. It is shown that such emission arises from a trap-like source filled 

with a weakly-anisotropic equilibrium plasma and a small addition of electrons which have a deficit 

of small velocities perpendicular to magnetic field. For many recorded events with mentioned fine 

spectral structure the instability processes responsible for the observed features are recognized: the 

background IV type continuum is due to the loss-cone instability of hot non-equilibrium electrons, 

and enhanced striped radiation results from double-plasma-resonance effect in the regions where the 

plasma frequency fp coincides with the harmonics of electron gyrofrequency fB: fp = s fB. The 

estimations of the electron number density and magnetic field in the coronal magnetic trap, as well 

as the electron number density and velocities of hot electrons necessary to excite the radiation with 

the observed fine structure are given. It is shown also that that in some cases several ensembles 

of non-equilibrium electrons can coexist in magnetic traps during solar flares and that its radio 

signature sensitively depends on the parameter constellation of the distribution functions of the 

different ensembles. 

Solar flares at millimeter and submillimeter wavelengths 

G. Trottet 1 , J.-P. Raulin 2 , C. Giménez de Castro 2 and P. Kaufmann 2 

1 Observatoire de Paris, LESIA-CNRS UMR 8109, Univ. P & M Curie and Paris-Diderot, 

Observatoire de Meudon, 92195 Meudon, France 

2 CRAAM Universidade Presbiteriana Mackenzie, São Paulo, Brasil 


Since 2000, the Solar Submillimeter Telescope (SST) has allowed us to observe more than ten major 

solar flares in the 200-400 GHz domain. The Köln Observatory for Submillimeter and Millimeter 

Astronomy (KOSMA) telescope has also detected four solar events in a similar frequency range during 

short observing campaigns in 2001 and 2003. While, for some events, the > 200 GHz emission appears 

as the extension toward high frequencies of the gyrosynchrotron emission seen in the microwave 

domain, other events exhibit an unexpected upturn towards the THz domain. Such spectra with 

positive slopes in the millimeter–submillimeter domain have been measured during both the impulsive 

and the gradual phases. In this presentation we briefly review submm observations of the major events 

recorded so far and the various emission processes that have been proposed to explain the spectral 

upturn during impulsive phases. We show that the gradual phase radio emission is most likely thermal 

bremsstrahlung radiated by an optically-thin coronal region over a wide frequency range and that 

at higher frequencies there is an additional contribution from opticall-thick sources located in the 

chromosphere. Such a source pattern is hardly consistent with the expectations from standard semiempirical 

models of the chromosphere and transition region during flares, which predict observable 

radio emission from the chromosphere at frequencies where the corona is transparent.


Diagnostics of electron transport in the chromosphere 

using hard X-ray solar flare observations 

M. Battaglia 1 , E. P. Kontar 1 and L. Fletcher 1 

1 School of Physics & Astronomy, University of Glasgow 


Despite observational advances in the past decades the structure of the chromosphere and the 

particle dynamics there is poorly understood. Using observations made with the Ramaty High Energy 

Spectroscopic Imager (RHESSI) we find the radial positions and sizes of footpoints as a function 

of photon energy in six flares with sub-arcsecond precision. The results allow us to investigate 

how the energetic electron propagate downwards in the chromosphere. Assuming collisional thicktarget 

transport we find that the hard X-ray sources are located between 600 and 1200 km above 

the photosphere. The vertical sizes (along the path of electron propagation) are up to a factor 4 

larger than predicted by the thick-target model, suggesting that additional effects such as magnetic 

mirroring, collisional pitch angle scattering, additional scattering due to wave-particle interactions 

and non-uniform target ionization have to be considered. We will discuss results from numerical 

simulations that include those processes and show how they could affect the source sizes measured 

with RHESSI. 

Measurments of solar flare anisotropy using RHESSI 

E. Dickson 1 and E. Kontar 1 

1 School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ 


The angular variation of high energy electrons during a solar flare is key to understanding the 

acceleration mechanism. The effect of photospheric albedo, Compton scattering of X-ray photons 

from the photosphere, should greatly influence the observed spectrum if the X-ray emitting electrons 

are highly beamed. Using RHESSI (Ramaty High Energy Solar Spectroscopic Imager) X-ray spectra 

and regularised inversion we estimate this the proportion of the electron flux directed downwards 

towards the photosphere compared to the electron flux directed towards the observer. The RHESSI 

flare database has been searched and analysis performed on all flares found to have statistically 

significant counts above 300 keV. In total 9 flares suitable for analysis were found. The anisotropy 

of these flares both over the entire impulsive phase and for shorter time intervals was measured and 

the flares have all been found to exhibit angular distributions which are consistent with isotropic. 

Particle acceleration in unstable twisted coronal loops 

M. Gordovskyy 1 , M. Bareford 1 and P.K. Browning 1 

1 Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL, UK. 


Fast magnetic relaxation in twisted coronal loops is considered to be one of the possible mechanisms 

behind energy release in solar flares. We study magnetic reconnection in twisted magnetic 

fluxtubes triggered by onset of ideal kink instability. Based on the obtained MHD model proton and 

electron kinetics is investigated using the relativistic guiding centre test-particle approach taking into 

account collisional scattering of accelerated particles. We discuss temporal evolution of high-energy 

proton and electron populations and possible observational implications.


Constraining turbulent acceleration models with imaging 

observations of thick-target coronal loops 

N.H. Bian 1 , A.G. Emslie 2 and E.P. Kontar 1 

1 School of Physics and Astronomy, Glasgow University, G12 8QQ, UK 

2 Department of Physics & Astronomy, Western Kentucky University, Bowling Green, KY 42101, USA 


RHESSI imaging observations of dense coronal sources allow an assessment of the density and 

volume of the acceleration region and, hence, of the specific acceleration rate of electrons to hardx-ray-producing 

energies, during solar flares. The value of this key quantity is used to constrain 

various turbulent acceleration models, in particular the level of electromagnetic fluctuations required 

for acceleration to occur at this rate in these models. This is combined with measurements of 

spectral indices and analysis of the variation of the source width with energy, resulting from turbulent 

transport of hard-X-ray-emitting electrons across the guiding magnetic field of the loop, which provide 

additional constraints on these models. 

The multifrequency Siberian radioheliograph. 

S.V. Lesovoi, A.T. Altyntsev, E.F. Ivanov, A.V. Gubin 

Institute of Solar Terrestrial Physics, Russia, Irkutsk, Lermontov Str. 126a 


The prototype of the multifrequency Siberian radioheliograph is described. The prototype consist 

of four parts: wide-band antennas with front-ends, analog back-ends, digital back-ends and a correlator. 

The prototype wide-band antennas are mounted on the outermost stations of the Siberian Solar 

Radio Telescope (SSRT) T-shape array. A signal from each antenna is transmitted to a workroom by 

the analog fiber optic link, laid in a tunnel. After mixing all signals are digitized and processed by 

the digital back-end receiver and transmitted to the correlator. The digital back-ends and the correlator 

are accessible by the local area network. This prototype is the first stage of the multifrequency 

Siberian radioheliograph development. The frequency range of the prototype is from 4 up to 8 GHz. 

It is assumed that the radioheliograph will consist of up to 100 antennas and will occupy stations 

of the West-East-South configuration of the SSRT. We plan to reach the sensitivity about 100 K for 

the snapshot image, the spatial resolution up to 13 arc-seconds at frequency of 8 GHz and the polarization 

measurement accuracy about a few percents. Currently the frequency switching observing 

mode is used. The prototype data are both circular polarizations at a few frequencies given by a list. 

The first observations by the prototype of solar microwave bursts are presented and discussed.The 

prototype data are online at http : //badary.iszf.irk.ru/prototype 10.php.


Microwave study of coronal sources in the early rise 

phase of solar flares 

A.T. Altyntsev 1 , G.D. Fleishman 2,3 , S.V. Lesovoi 1 and N.S. Meshalkina 1 

1 Institute of Solar-Terrestrial Physics, Irkutsk 664033, Russia. 

2 Department of Physics and Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 

Newark, NJ 07102 

3 Ioffe Institute, St. Petersburg 194021, Russia 


Study of pre-flare activity can advance our understanding of how the free magnetic energy is 

accumulated, stored, and then triggered for the explosive energy release of a flare. Using the SSRT 

(including the new 10 antenna radioheliograph observing at several frequencies simultaneously) and 

NoRH microwave observations with spatial resolution we study a number of events in which a pronounced 

increase of soft X-ray emission precedes noticeably the observed hard X-ray emission onset. 

Based on the X-ray analysis it was recently proposed that such pre-flare emission contradicts to 

the classical flare scenario with primary energy release going into electron acceleration. The microwave 

observations, however, show that nonthermal emission produced presumably by accelerated 

electrons with energy of several hundred keV appears as early as the soft X-ray emission, while the 

non-detection of the hard X-rays at that early stage of the flares seems to originate from a limited 

RHESSI sensitivity. The frequency of the spectrum peak is well below 10 GHz for the pre-flare microwave 

emission in all cases, which implies a relatively weak magnetic field at the radio sources. This 

is confirmed by the radio imaging suggesting that the regions of the microwave emission are more 

extended than the soft X-ray coronal sources. The emission mechanisms and plasma parameters of 

the microwave coronal sources and implication for energy release and electron acceleration in flares 

are discussed. 

Study of flare energy release using events with numerous 

type III-like bursts in microwaves 

N.S. Meshalkina 1 , A.T. Altyntsev 1 , D.A. Zhdanov 1 , S.V. Lesovoi 1 , 

A.A. Kochanov 1 ,Y. Yan 2 and C. Tan 2 

1 Institute of Solar-Terrestrial Physics, Lermontov St. 126a, Irkutsk 664033, Russia 

2 Key Laboratory of Solar Activity, National Astronomical Observatories, CAS, Beijing 100012, China 


The analysis of narrowband structures in radio bursts dynamic spectra allows to receive unique 

information about primary energy release mechanisms in solar flares. The observations with high 

spectral and spatial resolution have special significance and allow directly to associate values of 

frequency drift of type III-like bursts with exciter movement velocities along the flare loop. Practically, 

the similar measurements are possible due to simultaneous observations with the SSRT (5.7 GHz, in 

two high-order fringes; thus, two 1-d scans are recorded simultaneously within two frequency intervals) 

and NAOC spectropolarimeters (China) in 5.2-7.6 GHz frequency range. It was possible to estimate 

the velocity of plasma density increase in acceleration region of electrons and pitch-angle anisotropy 

in event with long series of bursts (Altyntsev et al. 2007). The results of analysis of unique series of 

type III-like bursts recorded during the flare 14 Apr 2002 are presented. Using-muliwavelength radio 

observations recorded by SSRT, NAOC, NoRP, RSTN (Learmonth) we studied the event with series 

of several tens of drifting microwave pulses and estimated their parameters. The burst drift rates 

range from -7 to 13 GHz/s. Using one-dimensional scans recorded with the SSRT interferometer at 

two different frequencies near 5.7 GHz, we have measured relative positions of burst sources and their 

velocities along a flare loop revealed from extreme-ultraviolet images. It is shown that the values 

of exciter displacements, their velocities, density gradient and mean drift rates are similar measured 

ones for the previous event.


The effect of self-induced electric field of electron beams on 

generation of Langmuir turbulence and resulting 

MW emission in flares 

V.V.Zharkova 1 and T.V.Siversky 1,2 

1 Department of Mathematics, University of Bradford, Bradford BD7 1DP, UK 

2 Department of Physics, L’viv University, Ukraine 


We present investigation of electron beam precipitation into a flaring atmosphere in the presence 

of collisional and Ohmic losses while generating Langmuir turbulence. The system of quasi-linear 

time-dependent kinetic equations describing the evolution of beams and Langmuir waves is solved by 

using the summary approximation method. We show that the self-induced electric field reduces the 

level and makes narrower the regions with low-hybrid Langmuir turbulence in the corona and upper 

chromosphere. The higher-hybrid Langmuir turbulence generated in a form of regular patterns in 

depth and energies is also reduced by the electric field to smaller number of patterns shifted to a 

narrower region in the upper corona. The resulting HXR and MW emission generated by electron 

beams in such flaring atmospheres is also presented and compared with observations. 

3D Solar null point reconnection simulation 

G. Baumann 1 , ˚A. Nordlund 1 , K. Galsgaard 1 , T. Haugbølle 1 and 

J. Trier Frederiksen 1 

1 Niels Bohr Institute, University of Copenhagen 


Starting from an extrapolated SOHO MDI magnetogram of the active region AR10191 on Nov 

16th 2002 (first studied by Masson et al. 2009), we used the Stagger MHD code as well as the 

particle-in-cell (PIC) Photonplasma code to investigate plasma dynamics, magnetic reconnection 

and particle acceleration in the neighborhood of a 3D coronal null point reconnection site. The 

reconnection is triggered by a bottom boundary driver, simulating the photospheric motion observed 

by SOHO. The MHD simulations use a stretched mesh with up to 1792 × 1024 × 640 mesh points, 

which allows a grid resolution of about 40 km over a region of about 40 × 30 × 6 Mm, centered around 

the null point, while at the same time covering a total volume of about 175 × 100 × 60 Mm. The PIC 

simulations use a cut-out of size about 44×25×16 Mm from the MHD simulations with uniform mesh 

sizes down to 25 km, and up to 100 billion particles. Values taken from the MHD run provide initial 

and boundary conditions for the PIC simulations. This first-of-a-kind multiscale study, combining 

observational data, MHD and PIC simulations and providing details of the coronal plasma behavior 

down to a mesh size of 25 km, was made possible by a NIC supercomputing grant and a PRACE 

supercomputing grant at the Jülich supercomputing center (FZJ). The PIC and MHD codes being 

used scale with better than 80% and 90% efficiency, respectively, up to 262,144 cores on the JUGENE 

system at FZJ.


Slow Magnetoacoustic Waves in Two-Ribbon Flares 

V.M. Nakariakov 1,2 , I.V. Zimovets 3 and M. Gruszecki 1 

1 Centre for Fusion, Space and Astrophysics, Physics Department, University of Warwick, Coventry CV4 7AL, UK 

2 Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 196140 St Petersburg, Russia 

3 Space Research Institute, Russian Academy of Sciences, Profsoyuznaya Street 84/32, Moscow 117997, Russia 


We demonstrate that disturbances observed to propagate along the axis of the arcade in tworibbon 

solar flares at the speed of a few tens km/s, well below the Alfvén and sound speeds, can be 

interpreted in terms of slow magnetoacoustic waves. The waves can propagate across the magnetic 

field, parallel to the magnetic neutral line, because of the wave-guiding effect due to the reflection 

from the footpoints. The perpendicular group speed of the perturbation is found to be a fraction of 

the sound speed, which is consistent with observations. The highest value of the group speed grows 

with the increase in the ratio of the sound and Alfvén speeds. For a broad range of parameters, 

the highest value of the group speed corresponds to the propagation angle of 25-28 degrees to the 

magnetic field. Compressible perturbations in the wave can trigger next energy release along the 

neutral line. This effect can explain the temporal and spatial structure of quasi-periodic pulsations 

observed in two-ribbon flares. 

Magnetacoustic shock formation near a magnetic null point 

M. Gruszecki 1 , S. Vasheghani Farahani 1 , V. M. Nakariakiov 1 and 

T. D. Arber 1 

1 Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, 

Coventry CV4 7AL, United Kingdom 


Interaction of nonlinear fast magnetoacoustic waves with a magnetic null point is investigated 

in the context of triggering solar flares. Propagation of fast, initially axisymmetric waves towards a 

two dimensional isothermal magnetic null point is modelled in terms of ideal magnetohydrodynamic 

equations. Dynamics of initially axisymmetric fast pulses of small amplitude is found to be consistent 

with the linear analytical solution of Craig and McClymont (1991). The increase in the amplitude 

leads to the nonlinear acceleration of the compression pulse and deceleration of the rarefaction pulse, 

and hence the distortion of the wave front. The pulse experiences nonlinear steepening in the radial 

direction, either on the leading or the back slopes, for the compression and rarefaction pulses, 

respectively. The nonlinear steepening leads to the generation of sharp spikes of the electric current 

density. As in the uniform medium, the position of the shock formation depends also upon the initial 

width of the pulse. Only sufficiently smooth and low-amplitude initial pulses can reach the vicinity 

of the null point, create there current density spikes, and hence initiate magnetic reconnection 

by seeding anomalous electrical resistivity. Steeper and higher amplitude initial pulses overturn at 

larger distance from the null point, and cannot trigger reconnection. The results are applied to the 

explanation of the observed progression of flaring energy releases along the neutral line in two ribbon 

flares.


Initiation and Early Evolution of CMEs: A Numerical 

Approach 

EPS Invited contribution 

C. Jacobs 1 , F. P. Zuccarello 1 and S. Poedts 1 

1 Centrum voor Plasma Astrofysica, K.U.Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium 


The magnetic field of the Sun structures the solar corona and provides the energy to drive violent 

solar eruptions, referred to as coronal mass ejections (CMEs). The current space missions provide 

unprecedented details of the Sun, in different wavelengths and from different view points. The recent 

solar minimum is a unique opportunity to investigate in detail the onset and propagation of CMEs. 

By means of numerical simulations, the initiation of a CME is studied in a simple set-up representing 

solar minimum conditions. The strength and morphology of the solar magnetic field is expected 

to have a determining effect on the CME properties, like size and speed. Large scale eruptions 

often disturb regions on the solar surface remotely from the eruption’s source region, pointing to the 

importance of the large scale coronal field. By means of 3D MHD simulations we aim to get a better 

insight in the onset of CMEs and the role of the magnetic field in this process. 

Magnetic Topology of Sigmoid Regions: comparison of a 

NLFFF extrapolation and an MHD simulation. 

E. Pariat 1 , A. Savcheva 2,3 , G. Aulanier 1 , E. DeLuca 2 , A. van Ballegooijen 2 

1 LESIA, Observatoire de Paris, CNRS, UPMC, Universit Paris Diderot, Meudon, France 

2 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA 

3 Boston University, Astronomy Department, Boston, MA, USA 


Sigmoids are magnetic structures in the solar atmosphere where highly sheared/twisted magnetic 

fields are believed to be present. Thanks to the high level of free magnetic energy, active 

regions with sigmoids possess a higher eruptivity. A standard 3D model for sigmoids assumes that 

the coronal emission is linked with currents forming at the interface between a twisted magnetic flux 

tube and a surrounding potential arcade. The topology of such 3D model predicts the existence of 

relatively long Bald Patches (BPs) regions and associated magnetic separatrices. However, magnetic 

field measurements of such sigmoid regions seldomly present such extended BPs. 

In the present study, we will present a topological analysis of a Non-Linear Force Free Field 

model of an observed active region with a sigmoid. We derived the connectivity map of the magnetic 

field in order to determine the location of the quasi-separatrix layers (QSLs). We show the correspondence 

of these QSLs with the electric current distribution responsible of the observed emission. We 

then compare the topology with the one of a three-dimensional magnetohydrodynamics numerical 

simulation of a solar eruption. We remark that, even though the observational and the numerical 

models results from very distinct assumptions and presents sensitively different magnetic structures 

(twisted vs. sheared fields), the underlying magnetic topology presents very strong similarities.


Simulated CMEs with multiple reconnection sites : 

A model for particle injection 

S. Masson 1 , S. K. Antiochos 1 and C. R. Devore 2 

1 Space Weather Laboratory, NASA Goddard Space Flight Center, 

8800 Greenbelt Road, Greenbelt, MD 20771, USA 

2 Laboratory for Computational Physics and Fluids Dynamics, Naval Research Laboratory, 

Washington, DC 20375, USA 


Magnetic reconnection in the solar atmosphere is believed to be the driver of most solar explosive 

phenomena. Therefore, the structure and dynamics of the coronal magnetic field are central to 

understanding solar and heliospheric activity. Important heliospheric manifestations of intense energy 

release linked to solar activity include the impact at the Earth of energetic particles accelerated during 

solar eruptions. 

Observationally, the magnetic configuration of active regions where solar eruptions occur, agrees 

well with the standard model of an eruption consisting of a flare and a coronal mass ejection (CME). 

According to the standard model, particles accelerated at the flare reconnection site should remain 

trapped in the CME. However, flare-accelerated particles frequently reach the Earth long before the 

CME does. 

We present a new model that may lead to injection of energetic particles onto open magnetic 

flux tubes connecting to the Earth. Our model is based on the well-known 2.5D breakout topology, 

which has a coronal null point (null line) and a four-flux system. A key new addition, however, is 

that we include an isothermal solar wind. Depending on the location of the open flux with respect 

to the null point, we find that the flare reconnection can consist of two distinct phases. At first, 

the flare reconnection involves only closed field, but if the eruption occurs close to the open field, 

we find a second phase involving interchange reconnection between open and closed. We argue that 

this second reconnection episode is responsible for the injection of flare-accelerated particles into the 

interplanetary medium. We will report on our recent work toward understanding how flare particles 

escape to the heliosphere. This work uses high-resolution 2.5D MHD numerical simulations performed 

with the Adaptively Refined MHD Solver (ARMS). 

This research was supported by the NASA SR&T and TR&T Programs and by an NPP appointment. 

Solar eruptions and the overlying background magnetic field 

A. Nindos 1 , S. Patsourakos 1 and T. Wiegelmann 2 

1 Section of Astrogeophysics, Physics Department, University of Ioannina, Ioannina GR-45110, Greece 

2 Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Strasse 2, 37191 Katlenburg-Lindau, Germany 


When a magnetic flux rope forms in the corona, it would expand and propagate outward unless 

its confinement is efficient. In active regions, the principal confinement agent is provided by the 

overlying background anchored magnetic field whose tension acts to hold the flux rope in place. 

Using magnetic field data from both the Helioseismic and Magnetic Imager (HMI) aboard Solar 

Dynamic Observatory (SDO) and the spectropolarimeter of the Solar Optical Telescope (SOT/SP) 

aboard Hinode spacecraft, we assess how the overlying field inhibits eruptions by calculating the 

temporal evolution of its decay index (i.e. how fast the field decreases with height) from a few days 

prior to a major coronal mass ejection (CME) until well after the eruption. The CME was associated 

with an X2.2-class flare that occurred relatively close to the disk center on 2011 February 15 in 

active region NOAA 11158. The early stages of the CME are further constrained by comparing the 

temporal evolution of the magnetic field’s decay index with data provided from the Atmospheric 

Imaging Assembly (AIA) imagers aboard SDO and the EUV imagers and white-light coronagraphs 

aboard Solar Terrestrial Relations Observatory (STEREO) spacecraft.


Coronal mass ejection-flare relationship and the topology 

of the erupting field 

B. Kliem 1,2 , T. Török 3 , and T. G. Forbes 4 

1 Institute of Physics and Astronomy, University of Potsdam, Germany 

2 Mullard Space Science Laboratory, University College London, UK 

3 Predictive Science, Inc., San Diego, CA, USA 

4 EOS Institute, University of New Hampshire, Durham, NH, USA 


Observations of coronal mass ejections (CMEs) and solar flares often show a correlation between 

the acceleration of the ejecta and the plasma heating and particle acceleration signified by the soft 

and hard X-ray emissions of the associated flare (the latter are thought to result from magnetic 

reconnection). This finding has stimulated the discussion of the CME-flare relationship, but at the 

same time it has made it difficult to find a conclusive answer as to whether an ideal MHD instability 

or magnetic reconnection is the prime cause of the eruptions. Numerical simulations of unstable 

flux ropes will be presented which successfully model CMEs. Some of these show a high degree of 

synchronization between the initial exponential acceleration of the flux rope, due to the ideal MHD 

instability, and the rise of reconnection. However, in others the reconnection sets in with a delay 

which can extend up to the phase after the flux rope’s acceleration peak. In addition, the reconnection 

flows generally lag behind the motions driven by the ideal instability, especially when the flux rope 

rise velocity nears the saturation phase. These properties suggest that the ideal MHD process is 

the primary driver of the coupled CME-flare phenomenon. The strong differences in the degree of 

synchronization are related to the magnetic topology prior to the eruption. Observations of CME vs. 

flare timing thus allow to infer which of the two basic flux rope topologies is relevant in a given event. 

Multi-spacecraft Study of the Kinematics of a Coronal 

Mass Ejection and its Associated Shock: EUV, 

White Light and Radio Signatures 

V. Ontiveros 1 , S. Patsourakos 1 , A. Nindos 1 , P. Corona-Romero 2 and 

J.A. Gonzalez-Esparza 2 

1 University of Ioannina, Greece 

2 Universidad Nacional Autonoma de Mexico 


It has been recently shown that CME-driven shocks can be directly observed and quantitatively 

analyzed from white light images. However, the full tracking of the 3D morphology and kinematics of 

the CME-shock system requires a set of high cadence observations, both in the inner and outer corona 

and well-separated viewpoints. We present here the multi-spacecraft analysis of the fast March 7th, 

2011 CME (∼ 1800 km/s) and its associated shock observed by the AIA/SDO, SECCHI/STEREO and 

LASCO/SOHO instruments. For the date of the event, the separation between Earth and STEREO 

A was 87 degrees, and Earth and STEREO B was 85 degrees which gives an ideal configuration for 

performing this kind of study. Using forward modeling, we find evidence of self-similar expansion 

of the shock and the CME up to 15 solar radii, but with a clear displacement of the CME leading 

edge and the shock wave front, that we attribute to the inhomogeneous nature of the background 

corona. We combine the measurements obtained by the different coronagraphs and EUV telescopes 

to track back the full impulsive phase to derive for the first time the full kinematic profile of the 

CME-shock from its source region up to 15 solar radii. This unique set of observations will allow us 

to determine whether the shock is still driven in coronagraph field of view. We also compare them 

with radio observations of a type II burst that was associated with the event. In addition we use 

our measurements as an input to an analytical model of the expansion of the ICME-shock system to 

follow their interplanetary evolution.


The Mechanisms for CME Onset and Rapid Acceleration 

S. K. Antiochos 1 , J.T. Karpen 1 and C.R. DeVore 2 

1 NASA Goddard Space Flight Center 

2 Laboratory for Computational Physics, NRL 


For understanding and eventually predicting coronal mass ejections/eruptive flares, two critical 

questions must be answered: What is the mechanism for eruption onset, and what is the mechanism 

for the rapid acceleration? We address these questions in the context of the breakout model using new 

2.5D MHD simulations with the Adaptively-Refined MHD Solver, the ARMS code. The adaptive 

mesh capability allows us to achieve ultra-high numerical resolution and, thereby, determine the 

influence of the effective Lundquist number on the eruption. The ARMS code also includes topology 

analysis tools that allow us to identify nulls in the system, and determine precisely the start of 

magnetic reconnection. Our calculations show that, at least, for the breakout model, the onset of 

reconnection external to the highly sheared filament channel is the onset mechanism. Once this 

breakout reconnection turns on, it cannot turn off and, hence, eruption is inevitable. However, as 

long as this is the only reconnection in the system, the eruption remains slow. We find that the 

eruption undergoes an abrupt “take-off” when the flare reconnection below the erupting plasmoid 

develops significant reconnection jets. We conclude that in fast CMEs, flare reconnection is the 

primary mechanism responsible for both flare heating and CME acceleration. The physical reason 

is straightforward; only flare reconnection can relax the erupting system down to a quasi-potential 

state, consequently it liberates the bulk of the free magnetic energy. We discuss the implications 

of these results for present and future observations and describe possible observational tests of our 

results. 

This work was supported, in part, by the NASA TR&T and SR&T Programs. 

Linking remote-sensing and in situ observations of coronal 

mass ejections using STEREO 

L. Rodriguez 1 , M. Mierla 2 , A. Zhukov 1,3 , E. Kilpua 4 , M. West 1 

1 Solar Terrestrial Center of Excellence, SIDC, Royal Observatory of Belgium., Av. Circulaire 3, 1180, 

Brussels, Belgium 

2 Institute of Geodynamics of the Romanian Academy, Jean-Louis Calderon 19 21, Bucharest 37, 

Romania, RO020032 

3 Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119992, Moscow, Russia 

4 Department of Physics, Theoretical Physics Division, University of Helsinki, Finland 


An important problem in solar terrestrial sciences is to discern whether a CME will arrive to the 

Earth. In particular, linking a CME with its corresponding interplanetary manifestation (ICME) has 

important implications for space weather. We use a model applied to coronagraph data from both 

STEREO spacecraft in order to calculate the angular width and direction of propagation of CMEs. 

These values are then propagated to 1 AU in order to quantitatively asses if an ICME should be 

seen in situ. By means of ACE data, we verify the existence of the corresponding ICME in order to 

validate our technique. Furthermore, we compare other characteristics of the CME/ICME pairs, for 

example their travel speed and arrival time at 1 AU.


Analysis of the characteristic coronal plasma parameters 

using homologous large-scale EUV waves 

I.W. Kienreich 1 , N. Muhr 1 , A.M. Veronig 1 , M. Temmer 1 and B. Vrˇsnak 2 

1 IGAM, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz, Austria 

2 Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kačićeva 26, HR-10000 


We study the wave pulse characteristics of four large-scale EUV waves, observed by STEREO- 

B, which occurred on Apr. 28-29, 2010. All waves were launched within 8 hours from the same 

source active region, propagated into the same Quiet Sun area and had similar shape and angular 

extent. Their wave kinematics was studied by the visual tracking method as well as the semiautomatic 

perturbation profile method, both methods led to very similar results of constant wave 

velocities in the range of ∼ 220 . . . 340 km/s. Furthermore we derived from the perturbation profiles 

the magnetosonic Mach-numbers peaking at values between Mms ∼ 1.04 . . . 1.09. In the case of 

homologous waves, it is valid to compare the wave pulse parameters, knowing that the four waves 

propagate in similar coronal background conditions. Our results show that the magnetosonic Mach 

numbers and velocities of the four waves are clearly correlated. Hence we conclude that the observed 

features are nonlinear fast-mode magnetosonic waves. As the Quiet Sun does not change noticeably 

within the 8 hours period, we can also estimate the background magnetic field strength in the low 

corona from the derived wave pulse parameters, obtaining values in the range of 1.5 and 3.5 Gauss. 

3D MHD numerical simulations of dome-shaped EUV 

waves from rotating Active Regions 

M. Selwa 1 , S. Poedts 1 and C.R. DeVore 2 

1 Centre for Plasma Astrophysics, K.U.Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium 

2 Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375, USA 


Recent STEREO observations enabled to study the structure and properties of EUV waves in 

more detail. Patsourakos & Vourlidas (2009) studied the basic 3D structure of a growing wave front 

finding it to have a dome-shaped structure that can be separated from an expanding CME. Later, 

Veronig et al. (2010) reported another observation of a dome-shaped large-scale coronal EUV wave. 

We investigate, by means of 3D MHD simulations, the formation of EUV waves as the result of the 

interaction of twisted coronal magnetic loops. The simulation is initialized with an idealized dipolar 

Active Region (AR) and is performed under coronal (low beta) conditions. A sheared rotational 

motion is applied to the central parts of both the positive and negative flux regions at the photosphere 

so that the flux tubes in between them become twisted. We find that the twisting motion results in 

a dome-shaped structure followed in space by a dimming and in time by an energy release (flare). 

Moreover, by applying a similar driver to different configurations of multiple dipoles we find that 

the shape of the dome depends on the topology of the AR. We investigate the relation between the 

properties of the initiation mechanism and the characteristics of the resulting EUV waves.


Session 8 

Origin and Properties of the Solar Wind


.


Origin and properties of the solar wind 


E. Marsch 1 



The solar wind originates in the Sun’s corona. Recent observational findings concerning its sources 

in various coronal magnetic structures are presented and discussed. A survey of the resulting solar 

wind streams is given, and their plasma components and basic properties are described. New empirical 

results and recent theories on solar wind acceleration are briefly discussed. The solar wind is 

permeated by plasma waves and turbulence stemming from different sources. The role that turbulence 

plays on various scales in solar wind thermodynamics is considered, and some related kinetic 

plasma processes are addressed. 

Transients in the solar wind and their solar origin during 

the solar activity minimum 

E.K.J. Kilpua 1 , C.O. Lee 2 J.G. Luhmann 2 and Y. Li 2 

1 Division of geophysics and astronomy, Department of Physics, University of Helsinki, Finland 

2 Space Sciences laboratory, University of California, Berkeley 


For this study, we focus on the solar cycle 23 minimum period (SC 23 minimum), and use near- 

Earth observations as well as those from STEREO. The SC 23 minimum was atypical in many aspects 

when compared to previous minimum periods. We will discuss different types of solar wind transients 

and their solar origins during this minimum period. Despite low solar activity interplanetary coronal 

mass ejections (ICMEs) and small ICME-like transients were regularly embedded in the solar wind. 

We found a divergence in the CME and ICME rates that we propose was due to the contribution 

by the slow and weak CMEs that deflected towards the equator, and also due to the significant 

changes in the streamer belt structure throughout this minimum period. During SC 23 ICMEs had 

on average lower magnetic fields than during the previous minimum implying intrinsically weaker 

CMEs or ICMEs that were crossed far away from the center. 

Large-Scale Variation of Solar Wind Electron Properties from 

Quasi-Thermal Noise Spectroscopy: Ulysses Measurements 

G. Le Chat 1 , K. Issautier 1 , N. Meyer-Vernet 1 and S. Hoang 1 

1 LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris Diderot; 5 Place Jules Janssen, 

92195 Meudon, France 


The transport of energy in space plasmas, especially in the solar wind, is far from being understood. 

Measuring the temperature of the electrons and their non-thermal properties is essential to understand 

the transport properties in collisionless plasmas. Quasi-thermal noise spectroscopy is a reliable tool for 

measuring the electron temperature accurately since it is less sensitive to the spacecraft perturbations 

than particle detectors. We apply this method to Ulysses radio data obtained during the first poleto-pole 

fast latitude scan in the high-speed solar wind, using a kappa function to describe the electron


velocity distribution. We deduce the variations with heliocentric distance between 1.5 and 2.3 AU in 

the fast solar wind at high latitude in terms of three fitting parameters: the electron density varies 

as ne ∝ R −1.96 ± 0.08 , the electron temperature as Te ∝ R −0.53 ± 0.15 , and the kappa index of the 

distribution remains constant at κ = 2.0 ± 0.2. These observations agree with the predictions of the 

exospheric theory. 

Plasma properties and evolution of brightenings in coronal 

holes and the quiet Sun from XRT, EIS, SOT and SUMER 

co-observations 

M. S. Madjarska, Zh.-H. Huang, J.-G. Doyle and S. Subramanian 

Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland 


We will present a statistical study on the plasma properties of brightenings identified in XRT 

Al poly images in an earlier paper by Subramanian et al. (2010) inside and at the boundaries of 

coronal holes. Comparison with the plasma characteristics of brightenings in the quiet Sun is also 

presented. The study is based on SUMER and EIS co-observations in spectral lines with formation 

temperatures from 10000 K to 12 MK. We will also report the analysis of the magnetic flux evolution 

associated with these brightenings from SOT co-observations. The nature of the brightenings will be 

discussed in the light of the obtained results.


Session 9 

Solar Data Assimilation and Space Weather Research


.


Current Standing of Space-Weather Forecasting: 

Aims, Tools, and Challenges 


E. Robbrecht 1 

1 Royal Observatory of Belgium 


Compared to meteorology, space weather is in its infancy. It’s a relatively new field of research 

that builds upon the knowledge of many different disciplines including research in solar physics and 

the sun-earth connection, empirical and numerical modeling, image processing, virtual observatories 

and data bases, development of supportive tools and science to operations. Any advancement in 

one of these sub-fields contributes to the improvement of real-time space weather forecasting. In 

this review-talk we will take a closer look at the key-problems that are crucial for improving realtime 

predictions. The space weather forecasters use the state-of-the-art knowledge in their daily 

assessment of space weather. Easy access to the most recent data is the basis for a good forecast. 

We will review the recent efforts that have been made to simplify data exchange and access. From 

the available data, tools and models the forecaster tries to extract a forecast for the next three days. 

We will discuss the outstanding questions of solar physics and space weather research that are key to 

improve our forecasting ability. Physical understanding is one thing, extracting the knowledge out 

of the available data in an efficient way is another problem. Triggered by this need, the field of solar 

image processing developed quickly, first in the margin of solar physics, but later as an important 

stand-alone discipline. We will overview applications that (are expected to) improve our forecasting 

ability. Lastly, we will consider the challenges in real-time numerical and empirical modeling that are 

important in becoming fully a 24/7 service. 

Solar Energetic Particle Research at IAA/NOA: a Space 

Weather Perspective 

O.E. Malandraki 1 , A. J. Tylka 2 , C. K. Ng 3 , L. C. Tan 1 , R. G. Marsden 4 , 

C. Tranquille 4 , K.−L. Klein 5 , B. Heber 6 , A. Papaioannou 1 , ∗ , 

P. K. Marhavilas 1 , K. Tziotziou 1 , N. Crosby 7 and R. Vainio 8 

1 Institute of Astronomy and Astrophysics, National Observatory of Athens, Greece 

2 Space Science Division, Naval Research Laboratory, Washington DC, 20375, USA 

3 College of Science, George Mason University, Fairfax, VA 22030, USA 

4 European Space Agency, (SRE-SM), ESTEC, Noordwijk, The Netherlands 

5 Observatoire de Paris, Meudon, France 

6 Christian-Albrechts Universitaet zu Kiel, Germany 

7 Belgian Institute for Space Aeronomy, Belgium 

8 University of Helsinki, Finland 

∗ also at the Nuclear and Particle Physics Section of the Physics Department, National and Kapodistrian 

University of Athens 


The Institute of Astronomy and Astrophysics (IAA) of the National Observatory of Athens 

(NOA) is currently strongly involved in two collaborative projects funded by the seventh framework 

program of the European Union, namely: SEPServer and COMESEP. SEPServer focuses 

on the implementation of a comprehensive and up to date Solar Energetic Particles (SEPs) analysis 

service including scientific data driven analysis both for 1 AU and for >1 AU using data 

from the SOHO/ERNE, SOHO/EPHIN, ACE/EPAM, ACE/SIS, WIND/3DP, Ulysses/HISCALE, 

Ulysses/COSPIN/LET and Ulysses/COSPIN/KET experiments. SEPServer will also provide for the 

first time the release of the HELIOS data set in a reasonable format and in full time resolution, thus 

making available data also for orbits inside 1 AU (down to 0.3 AU). SEPServer will enhance our


understanding of the source, acceleration and transport of SEPs which is directly related to Space 

Weather (SW) research progress. COMESEP sets out to develop tools for forecasting SEP radiation 

storms and geomagnetic storms based.It is foreseen that these forecasting tools will be incorporated 

into an automated operational European Space Weather Alert system, which is the COMESEP primary 

goal. Basic research activities on SW carried out at IAA/NOA within the framework of these 

two projects will be presented including the analysis of SEP and the associated electromagnetic emissions 

for selected case studies, the detailed study of the so-called reservoir effect in the heliosphere 

as well as the impact of the large-scale structure of the IMF on the SEP profiles and its SW implications. 

These project-related activities will provide the basis for future solar missions such as Solar 

Orbiter, in which IAA/NOA participates as a Co-Investigator (EPD instrument). The research leading 

to these results has received funding from the European Union Seventh Framework Programme 

(FP7/2007-2013) under grant agreements no 263252 (COMESEP) and no 262773 (SEPServer). 

The influence of the ambient solar wind flow on the 

propagation behavior of interplanetary CMEs 

M. Temmer 1 , C. Möstl 2 , T. Rollett 1 , A.M. Veronig 1 and B. Vrˇsnak 3 

1 IGAM-Kanzelhohe Observatory, Institute of Physics, University of Graz, Universitaetsplatz 5, 

A-8010 Graz, Austria 

2 Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 

3 Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000, Zagreb, Croatia 


The propagation behavior of coronal mass ejections (CMEs) in the interplanetary (IP) space is 

mainly influenced by the ambient solar wind flow. The interaction of CMEs with the solar wind can 

be expressed as drag force and manifests itself to decelerate CMEs that are faster than the ambient 

solar wind, whereas slower ones are accelerated until the CME speed is finally adjusted to the solar 

wind speed. With the SECCHI instrument suite aboard STEREO, CMEs can be observed during 

their entire propagation all the way from the Sun to 1 AU. In combination with in-situ measurements 

at 1 AU we are able to derive the direction and speed of a CME. This information is used as 

input to derive the kinematical behavior of well observed CME events in the IP distance regime, 

which is subsequently compared to the output from ENLIL (NASA/CCMC) MHD model runs of the 

background solar wind speed and to the drag force as expressed in analytical models. We present 

results of the effect of the background solar wind speed on the propagation behavior of well observed 

CMEs tracked from Sun to Earth. 

Image Processing, Pattern Recognition, and Data 

Assimilation in the SDO Era 


A.R. Davey 1 , and the SDO Feature Finding Team (FFT) 

1 Harvard Smithsonian Center for Astrophysics 


In the fall of 2008 NASA selected a large international consortium to produce a comprehensive, 

automated, feature-recognition system for a number of solar features and events including, Flares, 

Active Regions, Coronal Holes, Coronal Dimmings, Filaments and Jets etc. To be able to keep up 

with the SDO data stream these codes need to be modular in design, robust, and efficient.


The challenges of image processing or computer vision, are very different when the codes need to 

run autonomously in a continuous pipeline. Infrastructure to support the results is provided by the 

Heliophysics Event Knowledgebase (HEK), that resides at LMSAL and is the principal repository 

for the metadata produced by the Feature Finding Team (FFT) modules. Many of these modules 

work in a number of differing modes, such as providing both space weather triggers and also an in 

depth science mode. The FFT also produces a trainable module which provides a new method of 

detecting various user-defined solar features, based on image texture parameters, which is derived 

from techniques used to find abnormalities in mammograms. 

In this talk I will describe the progress we have made towards our goal of a comprehensive system 

for feature and event detection covering many different imaging processing techniques, the challenges 

we have faced, and some of the areas of image processing and pattern recognition where solar physics 

has room to improve. 

Solar Flare Forecasting: From probabilities to targeted 

predictions 

D.S. Bloomfield 1,2 , P.A. Higgins 1 , R.T.J. McAteer 3 and P.T. Gallagher 1 

1 Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2, Ireland 

2 Marie Curie Intra-European Fellow 

3 Department of Astronomy, New Mexico State University, Las Cruces, NM 88003, USA 


Solar flares mostly originate from active regions, with more complex magnetic field arrangements 

leading to more frequent occurrence and often larger magnitude flares. Historically-averaged soft 

X-ray flaring rates from individual McIntosh magnetic classifications are used to calculate Poisson 

probabilities of flaring in a 24-hour period. Forecast verification measures are used to determine 

the optimum probability threshold for converting flaring percentage probabilities into yes/no flare 

predictions, with differing thresholds presented for different space weather interest groups. 

A new solar prominence catalogue with SOPRA 

N. Labrosse 1 , S. Dalla 2 , J. Ren 3 , and S. Marshall 3 

1 SUPA, School of Physics and Astronomy, University of Glasgow, UK 

2 Jeremiah Horrocks Institute, University of Central Lancashire, UK 

3 Department of Electronic and Electrical Engineering, University of Strathclyde, UK 


We present SOPRA (Solar Off-limb Prominence Reconstruction Algorithm), an algorithm which 

automatically detects prominences above the limb in EUV images taken in the He II channel at 304 ˚A 

and subsequently reconstructs the structures to extract their morphological parameters. 

SOPRA determines the characteristics of radial intensity profiles outward from the limb and uses 

Support Vector Machines in order to classify them as belonging to prominence or other structures. 

Pixels detected as belonging to a prominence are then used as the starting point to reconstruct the 

whole object by morphological image processing techniques. 

The algorithm is applied to the entire SOHO/EIT data set and a catalogue of detected prominences 

is produced. We present the initial statistical analysis of this catalogue, and discuss its use for solar 

prominence research and for space weather monitoring. 

We also assess the performance of SOPRA when applied to SDO/AIA images.


.


Posters (per session, in alphabetical order)


.


Session 1 

Science with Cutting-Edge Heliospheric Missions 

P.1.1. Heights of X-ray, EUV and white-light sources in 

a limb flare observed by RHESSI and SDO 

M. Battaglia 1 , E. P. Kontar 1 

1 School of Physics & Astronomy, University of Glasgow 


X-rays, EUV and white-light emission are all signatures of energy deposition and heating in the 

solar atmosphere by flare accelerated particles. Soft X-ray and EUV loops represent hot plasma 

while hard X-rays and white-light emission are generally associated with energy deposition by fast 

electrons. A strong temporal correlation of hard X-ray with white-light emission has been found in 

the past and images suggest a high spatial association. However, the detailed spatial relations in 

terms of the height of the sources in the solar atmosphere and the energy deposition is still unknown. 

Combining RHESSI and SDO AIA and HMI observations of a limb flare, it is possible for the first time 

to not only infer the relative heights of the sources but the absolute heights above the photosphere. 

Observations of the positions of hard X-ray footpoints as a function of energy were used to infer 

the photospheric reference height. The hard X-ray footpoints are found at heights between 1000 and 

1700 km above the photosphere consistent with previous observations, while the AIA 1700 ˚A emission 

originates from below the RHESSI footpoints, at the photospheric level. The white-light emission is 

found to originate from a height of about 2500 km above the photosphere while the peak in other 

EUV channels is nearer 3000 km. This suggests that the bulk of the energy deposited stems from 

non-thermal electrons of energies as low as 8 keV. The collisional energy deposition rate calculated 

for these low energy electrons in the presented flare is more than sufficient to power the white-light 

and EUV emission. 

P.1.2. Absolute calibration of the VTT echelle spectrograph 

at the 1 m/s level with a laser frequency comb 

H.-P. Doerr 1 , T. Steinmetz 2,3 , R. Holzwarth 2,3 , T. Kentischer 1 and 

W. Schmidt 1 

1 Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, 79104 Freiburg, Germany 

2 Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany 

3 Menlo Systems GmbH, Am Klopferspitz 19a, 82152 Martinsried, Germany 


Optical frequency combs map the accuracy and stability of radio frequency references, such as 

atomic clocks, to optical frequencies. They emit an spectrum of exactly equidistant laser modes and 

the absolute frequency of the modes can be measured and stabilized to an RF reference. 

Frequency combs are available for the near infrared and visible spectrum, and the mode spacing 

and output power can be adjusted almost arbitrarily. For this reasons, Frequency combs are 

considered as the ultimate calibration source for astronomical spectrographs whenever high-precision 

absolute wavelength references are needed. A first successful proof of conecpt test of a so called 

astro-comb was done at the Echelle spectrograph of the German Vacuum Tower Telescope (VTT)


three years ago (Steinmetz et al. 2008). A calibration repeatability of only 9 cm/s was recently 

demonstrated by the same group at ESO’s HARPS spectrograph (Wilken et al. 2010). 

An astro-comb system tailored for the VTT spectrograph is currently beeing implemented in 

cooperation with the Max-Planck-Institute for Quantum Optics in Garching, Germany, and will be 

shipped to the VTT in late 2011. The astro-comb will cover the visible spectrum at 530 ± 50 nm with 

a mode spacing of 6 GHz (≈ 6 pm at 550 nm). Even though the VTT spectrograph was never designed 

for long-term stability, from the experience with the first test run and the theoretical performance 

characteristics of the instrument we expect an absolute repeatability at the 1 m/s level to be feasible. 

We will give an overview of the VTT laser frequency comb and the scientific questions we plan to 

address with the system. 

P.1.3. On the formation height of the SDO/HMI Fe 6173 ˚A 

Doppler signal 

B. Fleck 1 , S. Couvidat 2 and T. Straus 3 

1 ESA Space Operations Department 

2 Stanford Univ. 

3 INAF/OAC 


The Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) is 

designed to study oscillations and the magnetic field in the solar photosphere. It observes the full solar 

disk in the Fe i absorption line at 6173 ˚A. We use the output of a high-resolution 3D, time-dependent, 

radiation-hydrodynamic simulation based on the CO 5 BOLD code to calculate profiles F (λ, x, y, t) for 

the Fe i 6173 ˚A line. The emerging profiles F (λ, x, y, t) are multiplied by a representative set of HMI 

filter transmission profiles Ri(λ, 1 ≤ i ≤ 6) and filtergrams Ii(x, y, t; 1 ≤ i ≤ 6) are constructed for six 

wavelengths. Doppler velocities VHMI(x, y, t) are determined from these filtergrams using a simplified 

version of the HMI pipeline. The Doppler velocities are correlated with the original velocities in the 

simulated atmosphere. The cross-correlation peaks near 100 km, suggesting that the HMI Doppler 

velocity signal is formed rather low in the solar atmosphere. The same analysis is performed for the 

SOHO/MDI Ni i line at 6768 ˚A. The MDI Doppler signal is formed slightly higher at around 125 km. 

Taking into account the limited spatial resolution of the instruments, the apparent formation height 

of both the HMI and MDI Doppler signal increases by 40 to 50 km. We also study how uncertainties 

in the HMI filter-transmission profiles affect the calculated velocities. 

P.1.4. Differential Emission Measures from the Regularized 

Inversion of SDO and Hinode data 

I. G. Hannah 1 , E. P. Kontar 1 and N. Labrosse 1 

1 School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK 


Observations from SDO and Hinode provide an unprecedented view of plasma in the solar atmosphere. 

However, the inference of how much material is emitting at each temperature - the Differential 

Emission Measure DEM - from these data sets is an ill-posed inverse problem. We present a model 

independent regularization algorithm used in RHESSI X-ray software that makes use of general constraints 

on the form of the DEM. The regularization produces error and temperature resolution estimates 

on the calculated DEM, thus giving an objective criteria as to whether the underlying plasma 

distribution is iso- or multi-thermal. We also investigate how the kernel uncertainties influences the 

DEM and its accuracy. The algorithm is computationally fast making it ideal for the challenging


amounts of SDO data. We demonstrate this technique applied to a range of DEM models simulating 

three data types (SDO/AIA, Hinode/XRT and Hinode/EIS) highlighting the resulting temperature 

resolution and its dependence on both signal to noise and DEM. We also obtain the regularized DEM 

from coronal loop observations with SDO/AIA. 

P.1.5. Basics and prospects of in situ measurement of plasma 

and dust with electric antennas in the solar corona and the 

heliosphere 

N.Meyer-Vernet 1 , M. Maksimovic 1 , M. Moncuquet 1 , K. Issautier 1 , 

G. Le Chat 1 , A. Zaslavsky 2,3 , F. Pantellini 1 , I. Mann 4,1 , S. Belheouane 1 , 

S.D. Bale 5 , I. Zouganelis 6 

1 LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris Diderot; 5 Place Jules Janssen, 

92195 Meudon, France 

2 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA 

3 NASA Lunar Science Institute, USA 

4 Belgium Institute for Space Aeronomie, 3 Avenue Circulaire, 1180 Brussels, Belgium 

5 Space Sciences Laboratory, University of California at Berkeley, CA 94720, USA 

6 LPP, UPMC, Ecole Polytechnique, CNRS, Univ. Paris 11, 4 avenue de Neptune, 

94107 Saint-Maur-des-Fossés, France 


Radio and plasma wave instruments in space have proved to be efficient in situ detectors of plasma 

and dust on a number of missions. Plasma detection with electric antennas uses the technique of 

quasi-thermal noise spectroscopy, based on the voltage fluctuations induced by the random motion 

of ambient plasma particles. This enables one to measure in situ the plasma density, temperature 

and non thermal properties with a great accuracy and an effective collecting area much greater 

than the antenna physical cross-section. Dust detection with electric antennas relies on impact 

ionization of dust grains striking the spacecraft, producing plasma clouds whose electric field reveals 

dust properties. This yields a huge effective collecting area which may be the whole spacecraft. We 

illustrate the implementation of these techniques on Solar Probe Plus and Solar Orbiter, and the 

scientific interest of two basic applications: 1) measuring the density, temperature and non-thermal 

properties of electrons, which play a major role for heat transport in the corona and solar wind; 

2) measuring dust in the corona and inner heliosphere, in particular to determine the source of the 

interplanetary nanoparticles recently discovered with STEREO/WAVES. 

P.1.6. Spectropolarimetry with ZIMPOL-3 at the IRSOL 

observatory 

R. Ramelli 1 and M. Bianda 1 

1 Istituto Ricerche Solari Locarno, CH-6605 Locarno, Switzerland 


Thanks to the Zurich Imaging Polarimeter (ZIMPOL) installed at the IRSOL observatory in 

Locarno (Switzerland) we are able to perform spectropolarimetric observations with very high polarimetric 

sensitivity (10 −5 ). Recently we have implemented a new improved version of the system 

(ZIMPOL-3) and we are using it for different observing programs. These include for example scattering 

polarization observations near the solar limb, spectropolarimetry of prominences in the He-D3 

multiplet and a synoptic program to detect variation in the properties of the turbulent magnetic field 

in the solar atmosphere.


Session 2 

The Science of Future Heliospheric Missions and Telescopes 

P.2.1. The Spectrometer/Telescope for Imaging X-rays (STIX) 

on-board Solar Orbiter 

O. Grimm 1 for the STIX team 

1 ETH Zürich, Switzerland 


Solar Orbiter is a sun-observing mission proposed for the European Space Agency’s Cosmic Visions 

program. It will address questions on the interaction between the sun and the heliosphere, the 

accelerating mechanisms of the solar wind and energetic solar phenomena. The satellite will carry 

ten instruments for remote-sensing and in-situ measurements. Solar Orbiter is planned to be launched 

in 2017 and will approach the sun to 0.28 astronomical units, allowing unprecedented high-resolution 

measurements. 

The X-ray imaging spectrometer on-board Solar Orbiter is called STIX (Spectrometer/Telescope 

for Imaging X-rays). This contribution will give an overview of its scientific goal and cover the 

instrument design. 

STIX will help in understanding the acceleration of electrons at the Sun and their transport 

into interplanetary space. STIX will determine the intensity, spectrum, timing, and location of 

accelerated electrons near the Sun, which can then be tracked through the inner heliosphere by other 

instruments on Solar Orbiter. In this way, the magnetic link between the heliosphere and the Sun 

can be established. 

STIX uses indirect Fourier imaging. The sun is observed through pairs of fine grids, separated 

by 55 cm. The grids of one pair are slightly different in pitch and rotation angle and cast a Moire 

pattern on the detectors underneath. Count rates of X-rays passing the grids as function of energy are 

determined with CdTe semiconductor sensors. Each sensor is pixelized to sample the Moire pattern 

and to cover of an extended dynamic range in count rates. The sensors are bonded to front-end 

amplifier units and thermally coupled to a space-craft cold finger to operate below -20 deg Celsius. 

The instrument data processing unit allows autonomous operation over extended periods of time 

and interfaces to the space-craft. 

P.2.2. ChroMag: A Synoptic Chromospheric Magnetograph 

S. Tomczyk 1 , S.W. McIntosh 1 , R. Casini 1 , A.G. de Wijn and C. Bethge 1 

1 High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307, USA 


Understanding the complex and dynamic behaviour of the chromosphere is indispensable to improve 

our insight in a multitude of fundamental issues in solar physics that remain to be explained. 

Among these are the influence of the chromosphere on coronal magnetism and heating as well as its 

role in the coronal mass cycle, the origin and acceleration of the solar wind, the onset and temporal 

evolution of CMEs, and the impact of these phenomena on space weather. Obviously, the key ingredient 

to address these questions is to monitor chromospheric magnetism and activity in a synoptic 

manner. In spite of their importance and in contrast to full-disk measurements of magnetic fields in 

the photosphere, synoptic surveys of chromospheric magnetic fields have been treated as an orphan


in the past. Here, we introduce the Community Synoptic Chromospheric Magnetograph (ChroMag) 

instrument of the High Altitude Observatory in Boulder, Colorado. 

ChroMag is a filtergraph instrument designed to conduct synoptic measurements of chromospheric 

magnetic fields in the spectral lines of Hα, Ca II 8542 ˚A, He I 5876 ˚A, and He I 10830 ˚A. This will be 

done at a high cadence (< 1 minute) and with a spatial resolution down to 1.5 ′′ in an FOV of 2.5 solar 

radii. Spectropolarimetric measurements will be performed both on the full disk and in prominences 

above the limb, the latter being achieved with an occulter in the beam. ChroMag is intended as a 

project with open access for the community, which includes an open data policy as much as access 

to spectropolarimetric inversion tools for an easier interpretation of the data. 

We present the design of the instrument and the current status of a prototype which is currently 

assembled at the High Altitude Observatory. 

P.2.3. The Hanle Effect from Space for Measuring the 

Magnetic Fields of the Upper Chromosphere and Transition 

Region of the Sun 

Javier Trujillo Bueno 1 , Jiˇrí ˇStěpán 1 , Luca Belluzzi 1 , et al. 

1 Instituto de Astrofísica de Canarias; 38205 La Laguna; Tenerife; Spain 


We present some theoretical predictions concerning the amplitudes and magnetic sensitivities of 

the linear polarization signals produced by scattering processes in some UV and FUV spectral lines 

of the upper chromosphere and transition region, such as Lyα at 1215 ˚A and Mg ii k at 2795 ˚A. 

To this end, we have calculated the atomic level polarization (population imbalances and quantum 

coherences) induced by anisotropic radiation pumping in semi-empirical and hydrodynamical models 

of the solar atmosphere, taking into account radiative transfer and the Hanle effect caused by the 

presence of organized and random magnetic fields. The amplitudes of the emergent linear polarization 

signals are found to vary typically between a fraction of a percent and a few percent, depending on the 

scattering geometry and the strength and orientation of the magnetic field. The results shown here 

encourage the development of UV polarimeters for sounding rockets and space telescopes with the aim 

of opening up a true diagnostic window for magnetic field measurements in the upper chromosphere 

and transition region of the Sun.


Session 3 

The Sun as a Whole: Large-Scale Flows, Helioseismology, 

Magnetism, and the Solar Cycle 

P.3.1. The Sun as a Variable Magnetic Star: Decade-Long 

Stokes-Meter Observations in Different Spectral Lines 

M.L. Demidov 

Institute of Solar-Terrestrial Physics, Irkutsk, Russia (demid@iszf.irk.ru) 


Many efforts in recent years are directed to increase the spatial resolution of solar magnetic 

field observations in attempts to reach homogeneous structures in the instruments aperture, when 

interpretation of measurements supposed to be more simple. But practical achievement of such 

resolution is an uncertain task of future time and investigation of solar magnetism, using observations 

with low spatial resolution, up to the integral observations of the Sun-as-a-star (Solar Mean magnetic 

Field- SMMF), are still important and necessary. Besides solar physics, such investigations are useful 

for interpretation of measurements of others solar type stars and for some space-weather problems. In 

this study the results of SMMF spectropolarimetric observations simultaneously in several spectral 

lines in the vicinity of Fe I 525.02 nm, made at Sayan observatory in 1999-2011, are presented. 

Additionally, observations of Wilcox Solar observatory in this period of time are analyzed also. A 

special attention is devoted to study of temporal variations of the SMMF basic characteristics, in 

particularly of magnetic strength ratios in different combinations of data sets. 

P.3.2. Quiet Solar Magnetic Fields: Weak or Strong? 

M.L. Demidov 1 and H.Balthasar 2 

1 Institute of Solar-Terrestrial Physics, Irkutsk, Russia 

2 Leibniz Institute for Astrophysics Potsdam, Potsdam, Germany 


The small-scale nature of the quiet solar magnetic fields, covering the major part of the Sun’s 

surface, is not clear in some aspects, yet. The results of magnetic field strength measurements depend 

on the spatial resolution, the instrument, the used spectral line(s), and the data interpretation 

method. In this study, we analyze simultaneous full-disk Stokes-meter observations in 15 diagnostically 

important spectral lines including FeI λ523.29 nm and FeI λ525.02 nm. For the inversions we use 

the SIR code with the different model assumptions. Two types of inversion results for the magnetic 

elements are found, depending on the position on the disk and, probably, on the relationship between 

the Stokes V profiles of the selected spectral lines. In the first case, inversions show kG strengths, 

small filling factors and high temperatures, but rather weak strengths (less then 200 G), large filling 

factors and low temperatures in the other cases. A possible connection of the obtained results 

with the existence of strong and weak magnetic elements populations, as recently discovered by J.O. 

Stenflo (A&A, 2010, v.517), is discussed. We present some numerical experiments applying the SIR 

code to multi-line observations, which have impacts on the urgent calibration issues of SOHO/MDI 

magnetogram data.


P.3.3. Photometric properties of facular regions in the red 

spectral range 

I. Ermolli 1 , M. P. Rast 2 and S. Criscuoli 1 

1 INAF - Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio Catone (Roma), Italy 

2 Laboratory for Atmospheric and Space Physics, Department of Astrophysical and Planetary Sciences, 

University of Colorado, Boulder, CO 80309, USA 


Recent measurements by radiometers on-board the Solar Radiation and Climate Experiment 

(SORCE) have shown the irradiance in the NIR and other visible spectral ranges to vary in counterphase 

with the solar cycle. These results come unexpected by both observations and theoretical 

models developed so far, thus raising the question of the validity of the atmosphere models employed 

to describe the physical properties of the solar atmosphere. In particular, it has been suggested the 

observed variations to be caused by a temporal variation of the thermal stratification of facular regions. 

In order to examine this hypothesis,we have studied the variation of the photometric properties 

of magnetic features in the red continuum spectral range. We have analyzed full-disk images acquired 

since 1997 with the Precision Solar Photometric Telescopes located at Rome and Mauna Loa. We 

show that a fraction of the regions identified as ’faculae’ has negative contrast and that the relative 

number of these ’dark features’ changes with the solar cycle. 

P.3.4. Investigations of the quasi-periodic solar oscillations 

at the sunspots/active regions based on SOHO/MDI 

magnetograms 

J. Kallunki 1,2 , and A. Rieholainen 2 

1 Aalto University, Metsähovi Radio Observatory, Kylmälä, Finland 

2 University of Turku, Tuorla Observatory, Kaarina (Piikkiö), Finland 


In this study we try to find quasi-periodic solar oscillation in the sunspots / active regions based 

on the varying magnetic field strength (500-3000 G). We focus to investigate long (> 1 minute) 

and ultra-long (∼< 10 h) oscillation periods. The magnetic field synoptic maps were obtained from 

SOHO/MDI. Also, we try to give a preliminary physical explanations for existing solar oscillations. 

Wavelet (Morlet), Global Wavelet Spectrum (GWS) and Fast Fourier Transform (FFT) methods 

were used in the periodicity analysis. Significance level 99 % was used in periodicity analysis. 

Additionally, the Quiet Sun Level (QSL) signal and the instrumental effect were investigated and 

discussed. 

We found several oscillation periods in the sunspots and the active regions above significance 

level 99 %; 3-5 minutes and 2-8 hours (120-480 minutes). Additionally, we also give the physical 

interpretation and explanation for the detected quasi-periodic solar oscillations. The long periodic 

oscillations (3-5 minutes) can be explained based on the simple, one dimensional flux tube model. 

And respectively, the origin of the ultra-long periodic (2-8 hours) oscillations can be explained based 

on the shallow sunspot model.


P.3.5. The interesting long duration and large scale event on 

the solar disk in 24-th cycle 

J.Klimes, jr. 1 , J. Klimes, sr. 2 

1 Observatory Upice, Czech republic 

2 Observatory Upice, Czech republic 


This paper presented the very interesting event on the solar disk. It was started on 1-st June 

2010 and it is existing to date. Some examples of terrestrial and satellite observations of situation 

and their progression are demonstrated. 

P.3.6. Optimized recording and archiving of astrophysical 

processes 

M. Klvaňa, M. Sobotka and M. ˇSvanda 

Astronomical Institute, Academy of Sciences of the Czech Republic (v.v.i.), Fričova 298, 

25165 Ondˇrejov, Czech Republic 


A rapid development of instrumental and computer technologies is connected with steadily increasing 

needs for archiving of large data volumes. The current trend to meet this requirement 

includes a data compression and growth of storage capacities. This approach, however, has technical 

and practical limits. Another, not so frequent, method is a reduction of data volume by means of 

selection without losing the useful information. We describe a method of optimized archiving of solar 

activity processes observed in full-disc images. The aim of this method is to minimise the amount of 

stored data. 

Principle of the method: Only the best-quality images containing a new informational value are 

archived. The informational value assessment is based on the analysis of changes detected in the 

images. We present various types of changes, their significance for transfer of new useful information, 

algorithms for change testing, and some results of the tests. 

Our results will be utilized in development of software package for the full-disc telescope AFDT, 

a part of the project of the 4-m European Solar Telescope EST. This software will automatically 

detect, recognize, and archive active phenomena with minimum requirements for storage capacity, 

preserving the maximum of useful information. 

P.3.7. Current helicity in solar active regions and dynamo 

models with magnetic helicity balance 

K.M. Kuzanyan 1 , D. Moss 2 and D. Sokoloff 3 

1 IZMIRAN, Russian Academy of Sciences, Troitsk, Moscow region, 142190 Russia 

2 School of Mathematics, University of Manchester, Oxford Road, Manchester, M13 9PL, UK 

3 Department of Physics, Moscow State University, Moscow 119992, Russia 


The observed magnitude of current helicity (Zhang et al, 2010) can be produced either by the 

effect of rising magnetic loops, or generated by dynamo action before the process of convective upwelling 

and rising due to a buoyancy instability. Naive estimates show that these effects are of the 

same order of magnitude.


Given the fact that the observed helicity regularly varies with the solar cycle, we explore the 

point of view that the observed helicity is consistent with the helicity calculated from mean field dynamo 

models. We consider several increasingly complicated mean-field dynamo models with dynamo 

suppression mechanisms based on magnetic helicity balance, and obtain the corresponding current 

helicity butterfly diagrams. Then we compare these with those observed over two successive solar 

cycles (Zhang et al, 2010). 

This approach leads to a generally negative result. In spite of the fact that the obtained diagrams 

resemble somewhat the observations, we fail to reproduce some important features of the phenomenology. 

We illuminate the discrepancy between the available observations and simulations obtained and 

discuss possible developments of the nave interpretation. It appears that we are dealing with something 

much more complicated rather than a straightforward manifestation of the magnetic helicity 

balance which suppresses mean-field dynamo action. In particular, we suggest that a substantial part 

of observed current helicity may be produced by the rising of magnetic loops to the solar surface 

which can be considered as a tracer of the hydrodynamic (rather magnetic) part of the alpha-effect. 

We outline possible options that may help to reconcile theory and observations. 

Reference: 

Zhang, H., Sakurai, T., Pevtsov, A., Gao, Yu, Xu, H., Sokoloff, D. D., Kuzanyan, K.; Mon. Not. 

R. astr. Soc. Vol. 402, Issue 1, pp. L30-L33 (2010) 

P.3.8. Investigating large-scale flows in prominence cavities 

N. Labrosse 1 , B. Schmieder 2 , S. Gibson 3 , T. Kucera 4 and H. S. Hudson 5,1 

1 SUPA, School of Physics and Astronomy, University of Glasgow, UK 

2 LESIA, Observatoire de Paris, FR 

3 HAO/NCAR, Boulder, USA 

4 GSFC/NASA, Greenbelt, USA 

5 SSL, University of California, Berkeley, USA 


Flows have been observed and detected using their Doppler signature in EUV spectra inside 

prominence cavities. 

We use the observations of Hinode obtained in the period 24-26 April 2007 to investigate the 

characteristics of these flows and their evolution with time and as a function of temperature. 

We present the results of this investigation and discuss their implications for the understanding 

of prominence cavities in light of recent modelling of these structures as a flux rope surrounded by 

overlaying arcades. 

P.3.9. Source surface radius and its development during 

last three solar cycles 

E. Markova 1 , M. Belik 1 and P. Ambroz 2 

1 Observatory Upice, Czech Republic 

2 Astronomical Institute of the Academy of Sciences of the Czech Republic, Ondrejov, Czech Republic 


The source surface radius presents one of the boundary condition in the modeling of solar coronal 

magnetic field. Its value affects the computed coronal magnetic structures. The pictures of solar 

corona obtained during total solar eclipses and processed by special numerical method, show very 

faint structures, extended to the several solar radii, which represent a real magnetic situation in the 

corona. A value of the source surface radius was estimated through the analysis of their shapes. We 

discuss some problems of calculation of its value and the evolution of source surface radius during 

solar activity cycle.


P.3.10. Solar convection and differential rotation: a need 

for a new model 

V.L. Olshevsky 1 

1 Main Astronomical Observatory of NAS, 27 Akademika Zabolotnoho St., 03680 Kyiv, Ukraine 


Present knowledge of solar differential rotation and global-scale convection is reviewed. 

Theory of these phenomena has been developing for more than half a century, but our understanding 

is still far from the complete picture. Mean-field models were successful to produce solarlike 

differential rotation profiles, but they depend on underlying assumptions which often could not 

be justified from observations. A decade ago realistic numerical simulations of turbulent convection 

in rotating spherical shells became possible. Now the problem of solar differential rotation is 

generally considered to be solved. However, neither mean-field models, nor numerical simulations 

reach quantitative agreement with the results, obtained by helioseismology. There is a demand for 

realistic, three-dimensional simulations of turbulent convection in the Sun on a global scale. Preliminary 

results, obtained with modern unstructured LES solver, developed at the Center for Turbulence 

Research of Stanford University, suggest that such simulations are in the foreseen future. 

P.3.11. Solar dynamo evolution in the non-kinematic regime 

D. Passos 1,2,3 , P. Charbonneau 2 

1 CENTRA-IST, Lisbon, Portugal 

2 GRPS, University of Montreal, Canada 

3 Physics Dep., University of Évora, Portugal 


One of the most used tools to study the behavior and evolution of the large scale solar magnetic 

field is flux transport dynamo theory. Models based on this framework are very popular nowadays 

and have been used even for the prediction of upcoming solar cycles. Nevertheless, these models 

take into account the effect of solar meridional circulation mainly in the kinematic regime, i.e., the 

magnetic field does not affect the plasma velocity field. In this work we will address this problem 

by presenting evidence that the Lorentz force feedback of the magnetic fields in the meridional flow 

is important for the evolution of the solar cycle. We present a preliminary analysis of the relation 

between magnetic field and flows in the Global large-eddy simulation of Ghizaru et al ApJ 715, 2010. 

Afterwards the results obtained are used to build a simplified dynamo model with which we study 

the long term dynamics caused by the Lorentz feedback. We find that when this feedback action is 

subjected to small fluctuations, the resulting solar cycles show period doubling, chaotic regimes and 

even long periods of low activity (a.k.a. grand minima).


P.3.12. Simulation of the regime of two off-phase dynamo 

waves in a solar cycle and comparison with observations 

H. Popova 1 , S.I. Zharkov 2 and V.V. Zharkova 3 

1 Faculty of Physics, Moscow State University, Lebedeva 1, Russia 

2 Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, RH5 6NT UK 

3 Department of Mathematics, University of Bradford, Bradford BD7 1DP, UK 


We present the simulation results obtained from several modifications of Parker’s dynamo theory 

adopted for the interpretation of dynamo wave signs detected with the Principle Component Analysis 

technique from the analysis of the solar background and sunspot magnetic fields in the cycles 21-23. 

We identified two main latitude components of the opposite polarities in each cycle reflecting the 

two primary waves of the background magnetic field in each hemisphere travelling slightly off-phase. 

We attempt to reproduce the latitudinal distributions for these waves and study the phase relations 

between the weak background solar magnetic (poloidal) field and strong (toroidal) magnetic field 

associated with sunspots field. We compare the results obtained from several modifications of Parker 

dynamo theory with the characteristics of derived waves and discuss their implications on the solar 

activity. 

P.3.13. Recent progress on helioseismic measurements of the 

deep meridional flow with the Fourier-Legendre decomposition 

technique 

M. Roth, H.-P. Doerr and K. Glogowski 

Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, 79104 Freiburg, Germany 


We apply the helioseismic Fourier-Legendre decomposition (FLD) technique to long time series of 

Doppler velocity maps as provided by the GONG, MDI and HMI instruments to derive the velocity 

of the sub-surface meridional flow. 

The FLD technique was originally developed by Braun et. al (1987) to study p-mode absorbtion 

in sunspots but the concept can also be applied for meridional flow measurements (Braun et. al 

1998). The time-dependent oscillation signal on the surface is decomposed into poleward and equatorward 

travelling wave fields whose power spectra show a slight frequency shift that is related to 

the meridional flow in sub-surface layers of the convection zone. By means of a SOLA (Pijpers & 

Thompson 1992) inversion method, we derive the velocity of the sub-surface flow from the measured 

frequency shifts and the standard solar model ’S‘ (Christensen-Dalsgaard et. al. 1996). 

We report on the progress of our ongoing work in further improving the FLD technique and 

present recent results of FLD-based flow measurements obtained with data from GONG and HMI.


P.3.14. The mass loading of quiescent prominences from 

multi-spectral data 

P. Schwartz 1, 2 , P. Heinzel 1 , P. Kotrč 1 , U. Anzer 3 and Yu. A. Kupryakov 4 

1 Astronomical Institute, Academy of Sciences of the Czech Republic 

2 Astronomical Institute, Slovak Academy of Sciences, Tatranská Lomnica, Slovak Republic 

3 Max-Planck-Institut fuer Astrophysic, Garching, Germany 

4 Sternberg Astronomical Institute, Moscow, Russia 


From May through June this year a multi-spectral observing campaign of quiescent prominence 

took place. Observations were carried out in EUV by AIA/SDO, in soft X-rays by XRT on Hinode 

and in Hα by horizontal spectrographs of the Ondrejov observatory. Our aim is to make a statistics 

of the total masses of quiescent solar prominences. For calculations of the column mass values in 

a given prominence position we use an improved method of Heinzel et al. (2008). We take into 

account the possibility of non-symmetrical distributions of the coronal X-ray and EUV emissivity in 

front and behind the prominence. Hα intensities are used for estimations of the hydrogen ionization 

degree, a very important parameter for correct column-mass estimates. Then integrating the column 

mass over the whole area of a prominence, the total mass is obtained. We present results for one 

selected prominence observed during the campaign. We have been also testing the quality of data and 

reliability of the method. After this we will be able to estimate the total mass of all other observed 

prominences and make an extended statistics. 

P.3.15. The behaviour of the 17 GHz solar radius and limb 

brightening in the spotless minimum XXIII/XXIV 

C. L. Selhorst 1 , C. G. Giménez de Castro 2 , A. Válio 2 , J. E. R. Costa 3 , 

and K. Shibasaki 4 

1 IP&D - Universidade do Vale do Paraíba - UNIVAP, São José dos Campos, SP, Brazil 

2 CRAAM, Universidade Presbiteriana Mackenzie, São Paulo, SP, Brazil 

3 CEA, Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP, Brazil 

4 NoRH, Nobeyama Radioheliograph, Japan 


The current solar minimum has surprised the entire solar community because the spotless period 

is presently almost 2-3 years longer than the usual minima. To better understand this, we studied 

the variation of the solar radius and the polar limb brightening at 17 GHz, comparing the results 

from the minimum at the end of cycle XXIII with those of the previous one. Daily maps obtained 

by the Nobeyama Radioheliograph (NoRH) from 1992 through 2010 were analyzed. Whereas the 

variation of the solar radius at radio frequencies indicates the heating of the solar atmosphere due to 

solar activity, the limb brightening intensity depends on the organization of the polar magnetic field 

of the Sun, including the global dipole and the features formed around it. These features are more 

prominent during minima periods. As a common result, researchers have observed a decrease in both 

radius and limb brightness intensity at 17 GHz during the present minimum when compared with 

the previous one. The mean solar radius is 0 ′′ .9 ± 0 ′′ .6 smaller and the limb brightening reduced its 

intensity by around 20%. Both decrements are interpreted in terms of the weaker solar chromospheric 

activity of the present cycle. Measurement of the radius and limb brightening at 17 GHz can be used 

as an alternative solar activity index and should be included in the set of parameters used to predict 

future cycles.


P.3.16. Longitude and latitude variations of MBP 

characteristics on the solar surface as observed by Hinode/SOT 

D. Utz 1 , A. Hanslmeier 1 , O. Kühner 1 , A. Veronig 1 , R. Muller 2 and H. 

Muthsam 3 

1 IGAM, Institute of Physics, Karl Franzens University of Graz, Universitätsplatz 5, 8010 Graz, Austria 

2 Laboratoire dAstrophysique de Toulouse et Tarbes, UMR5572, CNRS et Universite Paul Sabatier Toulouse 3, 

57 avenue dAzereix, 65000 Tarbes, France 

3 Institute of Mathematics, University of Vienna, Nordbergstrae 15, 1090 Vienna, Austria 


The Suns dynamic processes on surface activity are strongly correlated to the solar magnetic 

fields. These magnetic fields are mostly generated by a subsurface dynamo thought to be situated 

in the tachoclyne. On the other hand it is believed that especially for small scale magnetic fields a 

surface dynamo on much smaller scales is acting. Magnetic fields on the Sun span from extended 

active regions down to smallest elements - single flux tubes. These single flux tubes can be seen in 

special wavelength bands as the G-band as bright points and are hence called magnetic bright points 

(MBPs). In this contribution we want to address the variation of characteristic parameters of MBPs 

as brightness as well as size with the longitude and latitude on the solar surface. For this purpose 

we use observational data of the Japanese/US/European space mission Hinode and its solar optical 

telescope (SOT). 

P.3.17. Ring diagram analysis of velocity and intensity HMI 

images 

A. Zaatri 1 , M. Roth 2 and H.P. Doerr 2 

1 Centre de recherche en astronomie, astrophysique and géophysique. Route de l’Observatoire, 

BP 63. Bouzaréah, Algiers, Algeria 

2 Kiepenheuer-Institut für Sonnenphysik. Schöneckstr.6 D-79104 Freiburg, Germany 


The Helioseismic and magnetic imager (HMI) is an instrument on the Solar Dynamics observatory, 

it is the successor of the MDI/SOHO instrument with a higher resolution (4kx4k) and a shorter 

cadence (45s). MDI already provided us with an imprecedented knowledge on the dynamics of the 

solar interior through helioseismic analysis of solar images. With the better resolution and cadence 

of HMI, many hidden aspects of the solar interior dynamics can be revealed, though. In this work, 

we analyze few days of HMI data using the ring diagram local helioseismology method in order to 

measure horizontal flows few Mm below the surface. Differential rotation and meridional circulation 

are indeed crucial ingredients for the understanding of the solar activity and dynamics. Both velocity 

and intensity images are used for these measurements and comparisons between them are discussed. 

Notably, a special interest is given to the measurement of horizontal flows near the limb using intensity 

images.


P.3.18. Proposed scenario for generation of the sunquake 

of 15 February 2011 

S.Zharkov 1 , L.M.Green 1 , S.A.Matthews 1 , B.Kliem 1 and V.V. Zharkova 2 

1 UCL Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, RH5 6NT UK 

2 University of Bradford, Bradford, UK 


The February 15, 2011, sunquake generated during the early phase of X2.2 flare is dissimilar to 

any of the previously reported photospheric quakes, having taken place outside of the regions of major 

Hard X-ray and white light emission. We apply acoustic holography to HMI data in order to locate 

photospheric acoustic sources associated with this flare and carry out frequency and time-distance 

analysis to determine properties of these sources. The locations and strengths of seismic signatures 

are compared with other AIA and RHESSI measurements. We propose quake excitation mechanism 

explaining the physics behind this event based on the results of our helioseismic investigation. Possible 

implications of these findings for physical processes in this flare are discussed.


Session 4 

Emergence and Evolution of Magnetic Flux in the Solar 

Atmosphere 

P.4.1. Evolution of large-scale magnetic fields over the solar 

cycle 19 derived from synoptic H-alpha charts 

E. V. Avramenko 1 , I. V. Abakumov 1 , D. I. Ponyavin 1 

1 Institute of Physics, St.Petersburg State University, Russia 

Ulyanovskaya str. 1, St.Petersburg, Russia 198504 E-mail: avramenko04@mail.ru 


We have analyzed Makarov and Sivaraman catalogue of magnetic field proxies inferred from Halpha 

observations during solar cycle 19. The idea is to trace evolution of large-scale magnetic fields 

on the Sun that formed the largest solar cycle of the past 400 years. The original filtering technique 

was applied to study large-scale organization of magnetic fields along latitude and longitude. Long 

lived recurrent patterns of magnetic features are found. The problem of multiple polar field reversals 

is discussed. 

P.4.2. Magnetic and dynamical properties of a forming 

sunspot from high-resolution observations 

N. Bello González 1 , F. Kneer 2 , R. Rezaei 1 and R. Schlichenmaier 1 

1 Kiepenheuer Institut für Sonnenphysik, Schöneckstr. 6, 79104 Freiburg, Germany 

2 Institut für Astrophysik Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany 


On July 2009 we witnessed the formation of the AR 11024 leading sunspot. Spectropolarimetric 

data were taken simultaneously with the (visible) GFPI and (IR) TIP II instruments together with 

imaging data in the G-band and Ca K channels, at the German Vacuum Tower Telescope (Tenerife). 

During 4.5 h we can follow the process of flux accumulation which transforms a protospot into a fullyfledged 

sunspot. The new incoming flux is provided by small magnetic concentrations originated in 

the AR emergence site. There, bipolar features co-spatial with elongated granules are observed. 

These bipoles diverge such that the poles draw apart, migrate and merge with their proper AR 

main polarity. While the penumbra develops, the umbral (total) flux keeps constant. After 4.5 h 

we measure an increase of the spot total flux from 17.4 × 10 20 Mx to 24.2 × 10 20 Mx. The penumbra 

forms in the spot side opposite to the emergence region and preferably as a continuation of light 

bridges. Previous to the (visible) penumbra formation, we observe an unexpected flow pattern in 

areas with inclined (>45 deg with respect to the vertical) magnetic fields. The typical Evershed (out- 

)flow appears only when penumbral filaments become apparent. Vortex flows found in the umbra as 

well as proper motions in light bridges hint towards a large-scale rotation of the sunspot magnetic 

field in deep sub-photospheric layers. We will present a scenario for sunspot formation and penumbra 

development based on these and other properties of our data set.


P.4.3. A comparative analysis of photospheric Bright 

Points in an Active Region and in the Quiet Sun 

F. Berrilli 1 , S. Criscuoli 2 , D. Del Moro 1 , I. Ermolli 2 , F. Giorgi 2 , 

P. Romano 3 , B. Viticchié 4 , F. Zuccarello 5 

1 Dipartimento di Fisica, Università degli Studi di Roma “Tor Vergata”, Via della Ricerca Scientifica 1, 

I-00133 Roma, Italy 

2 INAF - Osservatorio Astronomico di Roma, Via Frascati 33, I-00040, Monte Porzio Catone, Italy 

3 INAF Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy 

4 ESA/ESTEC RSSD , Keplerlaan 1, 2200 AG Noordwijk, The Netherlands 

5 Dipartimento di Fisica e Astronomia - Sezione Astrofisica, Università di Catania, Via S. Sofia 78, 

I-95123 Catania, Italy 


We have investigated the photometric and dynamic properties of photospheric Bright Points (BPs) 

observed in an Active Region and in the Quiet Sun. We have analyzed two data sets acquired with 

IBIS (Interferometric BIdimensional Spectrometer) at the NSO Dunn Solar Telescope on 2006, Oct 

2nd and Nov 21st, respectively. The former consists of spectral images of the Active Region NOAA 

10912 acquired along the Fe I line at 709.0 nm and the Ca I line at 854.2 nm and of simultaneous 

broad-band and G-band observations. The latter consists of spectro-polarimetric observations of 

the Quiet Sun along the Fe I doublet at 630.15 630.25 nm and simultaneous observations in white 

light and in G-band. The aim of this study is to exploit the high spectral, spatial and temporal 

resolution of IBIS in order to carry on a comparative analysis of the evolution and the dynamics of 

the photospheric BPs in regions characterized by different magnetic flux concentrations. 

P.4.4. Analysis of the spatial and spectral structures of 

complex active regions according to RATAN-600 observations 

V.M. Bogod 1 , T.I. Kaltman 1 , A.G. Stupishin and L.V.Yasnov 2 

1 Special astrophysical observatory, Saint-Petersburg, Russia 

2 Saint-Petersburg State University, Saint-Petersburg, Russia 


To study the structure of the solar atmosphere at the upper chromosphere,transition region and 

lower corona effectively used radio observations at microwaves. We present some results and methods, 

based on a detailed analysis of the intensity and circular polarization of radio emission in wide 

frequency range. These results were obtained on the RATAN-600 radio telescope, which the new 

spectral equipment installed, covering the 4.5 octaves with 1% frequency resolution. The study of 

height structure provided for both active regions with a stable simple magnetic structure and for 

complex active regions, which contain neutral line sources (NLS) above photosphere. 

In particular, the analysis of spectral and spatial structure during May 16-21, 2007 used for the 

complex active region NOAA 10956. According to the results of structural analysis of the active 

region, highlighted the cyclotron radio sources, the NLS sources and constructed the distribution 

of their magnetic field structure with height. The results of radio measurements of the magnetic 

field compared with the structure of the magnetic field, which is recovered by extrapolating the 

photospheric field, based on data obtained from satellites SOHO (MDI), HINODE. The extrapolated 

magnetic field used to calculate thermal cyclotron radiation. 

The calculation results are also compared with observations on the RATAN-600. Possible reasons 

for the differences between the calculated and observed characteristics of the radiation associated 

with the presence of the NLS source, the presence of irregularities in the distribution of electron 

temperature and density and a complex magnetic field topology.


P.4.5. Supersonic magnetic upflows observed with 

IMaX/Sunrise 

J.M. Borrero 1 , R. Schlichenmaier 1 and L.R. Bellot Rubio 2 

1 Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany 

2 Instituto de Astrofísica de Andalucía, Granda, Spain 


Very recently (ApJ, 2010, 723, L154) the instrument IMaX (Imaging MAgnetograph eXperiment) 

on-board the stratospheric balloon Sunrise has reported on the detection of many short-lived phenoma 

that appears at very small scales everywhere in the quiet Sun. Some of these events manifest 

themselves as upflows that are characterized by highly shifted (vLOS > 6 km s −1 ) circular polarization 

signals (Stokes V ), and they usually appear close to nearby patches of opposite magnetic polarities. 

Although magnetic reconnection appears as the most plausible explanation for these events, the limited 

spectral information around Fe I 5250 ˚A in the IMaX observations does not allow for a unique 

interpretation of the data. 

In this contribution we will present new results from the analysis of new IMaX data where the 

spectral line Fe I 5250 ˚A was sampled with much better spectral resolution. Thanks to this data set 

it is possible to study in more detail the possible scenarios that have been proposed as the driver for 

these events: magnetic reconnection, hot plasma cloud in the deep Photosphere, large gradients in 

the velocity and unresolved magnetic structures. We will present results from numerical experiments 

and synthetic Stokes profiles and compare them with IMaX observations in order to lend support or 

to rule out these different scenarios. 

P.4.6. Magnetic field cancellation events in the solar 

photosphere 

S. Danilovic 1 

1 Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany 


We study the evolution of small-scale mixed polarity field using realistic 3D MHD simulations. We 

concentrate on individual reconnection events and describe observational signatures that are likely 

to arise. We show how the event properties depend on the numerical simulation setup. Finally we 

compare our results with observations obtained with different instruments. 

P.4.7. Net Circular Polarization as a tool to measure the 

gradient with height of the penumbral magnetic field 

M. Franz 1 , J.M. Borrero 1 and R. Schlichenmaier 1 

1 Kiepenheuer Intitut für Sonnenphysik, Schöneckstasse 6, 79104 Freiburg, Germany 


We investigate the influence of the gradients with height of various atmospheric parameters on 

the total net circular polarization (N ). In our contribution, we demonstrate that at disk center, 

the correlation between N and Doppler velocity is larger for penumbral down-flows than it is for 

penumbral up-flows. This is due to a) the larger value of the average zenith angle of the magnetic 

field in down-flows and b) the larger difference between the zenith angles of the magnetic field of the 

individual atmospheric components (Franz 2011). Furthermore, we argue that only a decrease of the


magnetic field strength with optical depth can account for the negative N in the center-side penumbra 

of sunspots at large heliocentric angles. By means of spectral inversion of Stokes profiles, we show 

that a simple model atmosphere with linear gradients in Doppler velocity and magnetic field strength 

is sufficient to account not only for the distribution of N , but also for its amplitude. Our results yield 

a scenario in which the plasma velocity always increases with optical depth, while the gradient of the 

magnetic field strength with optical depth is either positive or negative, thereby accounting for the 

pattern of positive and negative N in the center-side penumbra (Franz et al. 2011). 

Franz, M.: 2011, PhD Thesis, Kiepenheuer Institute für Sonnenphysik 

Franz, M., Borrero, J. M., and Schlichenmaier, R.: 2011, A&A, (in preparation) 

P.4.8. Penumbral magnetic fields of opposite polarity 

M. Franz 1 and R. Schlichenmaier 1 

1 Kiepenheuer Intitut für Sonnenphysik, Schöneckstasse 6, 79104 Freiburg, Germany 


Evaluating HINODE data, we find Stokes V profiles with three lobes throughout the penumbra. 

Three lobe profiles (TLPs) show an additional lobe on the blue or red side of a regular Stokes V 

profile. If the additional lobe occurs on the blue side, it is of the same polarity as the regular Stokes 

V profile, while the additional lobe is of opposite polarity, if it occurs on the red side. For observations 

at disk center, our analysis of TLPs reveals that up-flow regions harbor magnetic fields of only one 

polarity, while at least 40% of all penumbral down-flows contain a magnetic component with opposite 

polarity (Franz, M. 2011). We sort Stokes V profiles according to the line shift of the respective 

Stokes I profiles (Franz et al. 2010). We find that for increasing Doppler velocity, the asymmetry of 

Stokes V profiles grows, then forms TLPs and sometimes even yields Stokes V profiles with four lobes 

(Franz et al. 2009). From this we conclude that both the vertical and the horizontal components 

of the Evershed flow are magnetized streams of plasma in a magnetized atmosphere. Finally, we 

elaborate on how TLPs can be used to put constraints on penumbral models. 

Franz, M. & Schlichenmaier, R. 2009: A&A, 508, 1453 

Franz, M. & Schlichenmaier, R. 2010, AN, 331, 570 

Franz, M.: 2011, PhD Thesis, Kiepenheuer Institute für Sonnenphysik 

P.4.9. On the Resolution of the Azimuthal Ambiguity in 

Partially Resolved Solar Vector Magnetograms 

M. K. Georgoulis 

Research Center for Astronomy and Applied Mathematics of the Academy of Athens 


The 180 ◦ azimuthal ambiguity is an intrinsic feature of vector magnetic field measurements relying 

on the Zeeman effect. To properly interpret such data, the ambiguity needs to be resolved or removed 

in advance. In addition, given the fine, fibril structure of solar magnetic fields, even the most sensitive, 

spatially and spectrally, vector magnetographs fail to fully resolve a given magnetic structure and this 

incurs further problems for the various azimuth disambiguation techniques. In a recent work, Leka 

et al. (2009, Solar Phys., 260, 83) claim that a category of azimuth disambiguation methods, those 

relying on the physical calculation of potential and non-potential magnetic fields, fail to correctly 

resolve the ambiguity in a set of partially resolved, synthetic test data. They also maintain that a 

given optimization method works much better in such cases. 

Here I show that the construction of these test data, not the limited spatial resolution, is the reason 

for the failure of physics-based disambiguation methods. Even simplistic disambiguation methods can 

almost completely resolve the ambiguity under the same conditions of unresolved structure provided


that the test data are defined for the semi-infinite space above the assumed lower boundary, which 

is a realistic expectation for solar magnetic fields. The test data of Leka et al. are defined only 

within a narrow layer above the boundary which creates fields not met in the real Sun, thus disabling 

physics-based methods that are more adapted to solar magnetic fields. Instead of this problem, Leka 

et al. mis-attribute the failure of physics-based methods to the limited spatial resolution. Therefore, 

an appropriate test to identify the best-performing azimuth disambiguation ideas and algorithms is 

still pending. 

This work is supported by EU’s Seventh Framework Programme under grant agreement n ◦ 

PIRG07-GA-2010-268245 and has been accepted for publication in Solar Phys. 

P.4.10. Spectropolarimetry of orphan penumbrae 

J. Jurčák 1 and L.R. Bellot Rubio 2 

1 Astronomical Institute of the Academy of Sciences, Fričova 298, 25165 Ondˇrejov, Czech Republic 

2 Instituto de Astrofísica de Andalucía, Apdo. de Correos 3004, 18080 Granada, Spain 


Orphan penumbrae, i.e. penumbrae without any adjacent umbrae, are occasionally observed in 

emerging active regions. We present two examples of evolution of such structures observed by the 

Hinode spectropolarimeter. Using the inversion code SIR, we retrieved the plasma parameters in 

the orphan penumbrae and surrounding sunspots assuming constant values of these parameters with 

height. From the resulting maps of magnetic field strength and inclination it is clear that the orphan 

penumbrae are observed between regions of opposite polarity. As the inclination changes with time, 

pores are formed at either one or both sides of the orphan penumbrae. The connection between these 

pores and orphan penumbrae are not always clear from continuum intensity maps. The magnetic 

field strength in the orphan penumbrae is around 800 G and not varying strongly. Highest values 

of magnetic field strength are observed close to regions where the pores appear. Similar magnetic 

field strengths are observed also in regular penumbrae, but there is a strong dependence on the 

position within the penumbra as we observe fields around 1700 G at the inner penumbra and 600 G 

at the outer penumbra. The maximal (100 ◦ ) and minimal (40 ◦ ) value of magnetic field inclination 

are comparable in the orphan and regular penumbrae. In most of regions in orphan penumbrae the 

resulting magnetic field inclination is around 90 ◦ , i.e. the field is nearly horizontal, while in regular 

penumbrae there is a smooth increase of inclination from the inner to the outer penumbra. The 

absolute values of line-of-sight velocity are slightly larger in the orphan penumbrae compared to the 

regular penumbrae. The flow is oriented along the penumbral filaments and nearly horizontal as it 

disappears in observations taken close to the disc centre. In some parts of the orphan penumbrae the 

flow is directed towards the stronger magnetic field region. 

P.4.11. Modeling of microwave emission and magnetic 

structure of active region 

T. I. Kaltman 1 , V. M. Bogod 1 , L. V. Yasnov 2 and A. G. Stupishin 2 

1 St. Petersburg branch of Special Astrophysical Observatory 

2 Radio Physics Research Institute, St. Petersburg State University 


Simulations of the microwave emission of solar active regions are presented. The calculations 

are done on the base of photosphere magnetic field measurements extrapolated to the corona. The 

observational data of HINODE and SOHO (MDI) satellites are used. 3D method of magnetic field 

extrapolation by nonlinear force-free approximation is elaborated. The microwave emission of solar


regions is calculated on the base of the reconstructed magnetic field with simple electron density and 

kinetic temperature distributions. Thermal gyroresonance and free-free mechanisms of emission are 

taken into account. 

The characteristics of simulated radio emission are compared with ones of the observational data of 

RATAN-600: the one-dimensional scans at different wavelengths of the microwave range, the spectra 

of full and polarized flux, the source sizes, the brightness temperature and a degree of the polarization. 

Spatial and spectral polarized structures of emission are analyzed. The general accordance between 

the model calculations and the observational data is reached after the correct fitting of the model 

parameters, this procedure allow to estimate the values of electron density and temperature of plasma. 

The model calculations provide appropriate tools to give a more precise definition of the effective 

heights of emission, to calculate an optical depth of the different gyro resonance levels and to draw 

an output fine structure of the brightness temperature distributions over the source region. Some 

discrepancies are discussed: too smooth modelled scans of emission and the low values of the modelled 

flux emission on the longer wavelengths compared to the observational data. Some problems could 

be explained by the simplicity of the model, but the stronger magnetic fields at coronal heights are 

steel needed. 

P.4.12. The horizontal component of photospheric plasma 

flows during the emergence of active regions on the Sun 

A.I. Khlystova 1 

1 Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia 

e-mail: hlystova@iszf.irk.ru 


The dynamics of the horizontal component of photospheric flows is analyzed at places where 

magnetic fields of solar active regions emerge. Several active regions emerging on the edge of the 

solar disk are considered. Full disk magnetograms and Dopplergrams with one minute temporal 

resolution obtained by the space observatory SOHO/MDI were used in the research. The analysis 

has revealed increased negative velocities at the polarity inversion line as well as increased positive 

velocities at the magnetic pole distant from the disk center. The structure observed in the velocity 

field forms when the magnetic field starts to emerge. It occupies an extensive region and exists several 

hours, the velocity values essentially surpass the convection velocities. An interpretation of the flows 

observed in the photospheric plasma is given. 

P.4.13. Regularities connected with the emergence of active 

regions at the solar photospheric level 

A.I. Khlystova 1 

1 Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia 

e-mail: hlystova@iszf.irk.ru 


This report presents a statistical investigation into the relationships between the magnetic field 

parameters and the plasma flow velocities during the first hours of the emergence of active regions at 

the solar photospheric level by using of SOHO/MDI data. The active regions under consideration have 

different spatial scales, emerge at different distances from the solar disk center and are isolated from 

large concentrations of existing magnetic fields. The following relationships are considered: 1) the 

Doppler velocity values and position of emerging active regions on the disk; we also make comparison 

with convective flow velocities of the quiet Sun; 2) the Doppler velocities and the maximum strength


of the magnetic field and the growth rate of the total magnetic flux separately for active regions 

emerging at the center and edge of the disk; 3) the growth rate of the total magnetic flux and the 

maximum strength of emerging magnetic fields; 4) the magnetic field parameters and plasma flow 

velocities in the first hours of emergence and the maximal phase of active region evolution. 

P.4.14. Reconnection and CME/Flare initiation: a grad 

computational challenge 

Giovanni Lapenta, Lapo Bettarini, Stefaan Poedts 

Katholieke Universiteit Leuven 


Following the example of the GEM challenge, the Soteria and SWIFF networks initiated a new numerical 

Grand Challenge: the comparison of models for coronal mass ejection and solar flare initiation 

by means of numerical codes using different theoretical approximations within the magnetohydrodynamics 

theoretical framework: 

Ideal Magnetohydrodynamics 

Resistive Magnetohydrodynamics (Different resistivity) 

Zero beta Magnetohydrodynamics 

Two fluid theory (with comparisons to kinetic) 

The aim is to establish useful benchmarks for different codes now and in the future. 

The challenge is described in detail on wikipedia: 

http://en.wikipedia.org/wiki/Soteria FP7 Network 

and on the web: 

http://soteria-space.eu/initiation.php 

We present the typical results, highlighting in particular the role of reconnection, discussing its 

possible presence in turbulent and laminar form. 

P.4.15. Statistical Analysis of Hinode/EIS Spectra during 

Flux Emergence 

E. Lee 1 , D.R. Williams 2 , L.M. Harra 2 , and G. Lapenta 1 

1 Centrum voor Plasma-Astrofysica, Katholieke Universiteit Leuven, Belgium 



EUV spectroscopy is a powerful remote-sensing tool that provides information about astrophysical 

plasma at scales unseen by even the largest telescopes available today. Hinode’s EUV imaging 

spectrometer is uniquely equipped to diagnose plasma conditions (e.g., average density, formation 

temperature), as well as motions at resolved scales (10 6 ∼ 10 9 m), through Doppler line shifts, and 

at “unresolved” scales, through line broadening. Since the kinetic-level information is only available 

in a statistical sense, the quality of the data depends critically on the instrument’s ability to collect 

sufficient photon counts. Other factors include careful calibration and other processing of the data. 

In this study, we observe the evolution of 1” slit raster data during flux emergence using EUV 

emission lines at multiple coronal temperatures. We follow a number of quantities related to ensemble 

statistics to describe the state of the coronal plasma, and we describe a variety of tools for 

both “objective” and “biased” improvement of the measured quantities. These tools involve careful 

selection of data based on profile smoothness (objective) and quality of fits to various profile shapes


(biased). In addition, we apply techniques to improve the signal-to-noise ratio in both objective and 

biased ways. Using data measured by EIS during quiescent and flux emergence conditions, we show 

the affect of applying each selection and de-noising method on deriving statistical conclusions about 

the coronal plasma. Finally, we compare the velocity distributions derived from spectroscopic data 

to those acquired from test particle simulations. 

P.4.16. Large-scale magnetic field of the Sun and activity 

development in cycle 24 

A.V. Mordvinov, V.M. Grigoryev and V.S. Peshcherov 

Institute of Solar-Terrestrial Physics, Russian Academy of Sciences, Siberian Branch, Irkutsk, Russia 


Evolution of a large-scale magnetic field of the Sun in the current activity cycle has been studied 

using a tomographic algorithm. The radial and toroidal components of the solar large-scale magnetic 

field were deduced from the analysis of the line-of-sight component of magnetic field in selected 

photospheric points passing through the solar disk. A regularization algorithm was developed to 

obtain a robust solution of the inversion problem. Magnetograms of the Wilcox solar observatory 

and similar data from solar telescopes of operative forecast of the Sayan and Baikal observatories 

were used. Heliographic maps of emerging segments of the toroidal magnetic field revealed the solar 

large-scale magnetic field evolving during cycle 24. During ascending phase of activity, the toroidal 

magnetic field indicates a drift of the sunspot zones with heliolatitude. The drift also manifests itself 

in changes of the rotation rate of the mean solar magnetic field. Large sunspot groups and complexes 

of activity causally depend on the significant toroidal magnetic field of the Sun. The study was 

supported by the RFBR grant 11-02-00333. 

P.4.17. Center to limb variation of granular properties 

F. Rubio da Costa 1 , A. Feller 1 and S. K. Solanki 1 

1 Max-Planck Institut für Sonnensystemforschung, Max-Planck-Straße 2, 37191 Katlenburg-Lindau, Germany 


The Sunrise balloon-borne solar observatory had onboard an imaging vector polarimeter, IMaX 

(Imaging Magnetograph eXperiment) which observed the granulation of the Sun in the four Stokes 

parameters for several days. 

Using the high resolution continuum images, we focused on the solar granulation at different positions 

of the solar disk: using a pattern-recognition algorithm based on multi level tracking (Bovelet 

& Wiehr, 2001) and expanding the segmented structures to cells (Hirzberger et al., 2007), we characterized 

the structure of the solar granulation for different values of mu, in order to study how its 

properties change from the centre to the limb of the Sun.


P.4.18. Photospheric Flux Cancellation and the Build-up 

of Sigmoidal Flux Ropes 

A. Savcheva 1,3 , L. Green 2 , E. DeLuca 3 and A. van Ballegooijen 3 

1 Boston University, Astronomy Department, Boston, MA02215, USA 

2 Mullard Space Science Laboratory, University College London, Dorking, UK 

3 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA02138, USA 


The magnetic structure of sigmoidal active regions is generally associated with the presence of 

a twisted flux rope held down by a potential arcade. Sigmoidal regions are often associated with 

solar eruptions and hence understanding how sigmoids develop and evolve is vital for getting insight 

into the mechanisms that lead to these eruptions. There are competing theories of how sigmoidal 

flux ropes develop - by flux emergence, cancellation, and/or footpoint motions. We look at how 

flux cancellation in several sigmoidal regions, observed with XRT and AIA, affects the buildup of the 

underlying flux ropes. We utilize MDI and HMI magnetograms to quantify the flux cancellation. The 

flux rope insertion method is used to construct non-linear force free field models of the regions, which 

provides the 3D magnetic field structure and current distributions. We present magnetic maps with 

overlaid 3D flux rope structures. We show a correlation of the locations of flares and bald patches 

with flux cancellation events. We demonstrate that free energy and helicity are injected into the 

flux rope at the locations of flux cancellation. We remark on systematic changes in the flux rope 

parameters and geometry. We show how the flux ropes energy and flux budget change in time in 

response to the active flux cancellation. 

P.4.19. Spectroscopic capabilities of C I 538.0 nm in the 

sunspot penumbra 

Rolf Schlichenmaier 

Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany 


A major breakthrough in Sunspot physics was recently accomplished by realistic simulations of 

entire sunspots in a box (cf. Rempel, M. 2011, ApJ 729, 5). These results for the first time offer 

an overall and consistent model of sunspots. However, important aspects of this model have not yet 

been confirmed by observation. Among others, the predicted presence of cool downflows at the sides 

of filamentary hot upflows awaits observational confirmation. 

In a recent paper, Joshi et al. (2011, ApJL 734, L18) claim the detection of cool convective 

downflows in the penumbra using C I 538.0 nm. In this contribution we will challenge these findings by 

investigating the formation properties of this line. This line is characterized by a very high excitation 

potential of 7.68 eV, thus commonly classified as ’hot’. We will present evidence on the basis of (1) 

empirical models of the penumbral atmosphere and (2) line synthesis of Rempel’s simulation box. 

From these considerations, we expect that the line depression in dark filaments amounts to less than 

5%. To measure such a weak line seems a very challenging task for a spectrometer that is based on 

wavelength scanning with two Fabry-Perot-Interferometers. 

We conclude that cool ’convective’ downflows in the penumbra can only be observed with C I 

538.0 nm, if one is capable to resolve line depression on the order of a few percent, and if line blends 

in such cool atmospheres can be excluded.


P.4.20. Emergence of magnetic flux, twist and torsion 

B.Schmieder 1 , G.Aulanier 1 and P.Démoulin 1 

1 Observatoire de Paris, 92195 Meudon, France 


Some observational examples of flux emergence and their signatures from the photosphere to the 

corona will be presented. Flux emergence does not lead automatically to instabilities. These events 

show that unstable systems come from the twist or the shear brought by the emerging flux or by 

rotation of sunspots after emergence initiating electric currents. These observations are supported 

by MHD modelling. 

P.4.21. Reconstructed coronal magnetic field and 

radioemission of the solar active regions 

A.G. Stupishin 1 , V.M. Bogod 2 , T.I. Kaltman 2 , and L.V. Yasnov 1 

1 St.Petersburg State University, St.Petersburg, Russia 

2 Special astrophysical observatory of Russian Academy of Sciences, Russia 


In this work we made a comparison of the magnetic field of solar active region obtained by 

different methods. First, linear and non-linear force-free magnetic field was reconstructed by the field 

measured on the photosphere (Hinode Solar Optical Telescope instrument) and model calculation of 

radioemission was proceeded. Second, spatial structure of the field was estimated by the observations 

of radioemission on RATAN-600 radiotelescope in the range 6-16 GHz. To avoid complexity active 

regions of simple structure near the centrum of solar disk were chosen. 

It was shown that force-free magnetic field approach is insufficient for these active regions to 

describe observing radioemission. Magnetic field at the heights of radioemission (2-3 Mm) should be 

stronger (up to 25%) that reconstructed one to explain observing sizes of radiosources in polarized 

emission at the high frequencies. It can indicate that non force-free terms (such a plasma pressure 

and gravity) should be taken into consideration. 

Comparison of model calculations and observation also shows that reconstructed magnetic field 

cannot explain the existence of small polarized radiosource observed at low frequencies. It can be 

related with fine structure of magnetic field (existence of narrow but strong magnetic tubes) which 

is missed by photospheric observation because of finite spatial resolution.


P.4.22. On the shape of active region coronal loops observed 

by Hinode/EIS. 

P. Syntelis 1 , C. Gontikakis 1 , C.E. Alissandrakis 2 , M. Georgoulis 1 and 

K.Tsinganos 3,4 

1 Research Center for Astronomy and Applied Mathematics, Academy of Athens, Soranou Efessiou St 4, 

11527 Athens, Greece 

2 Section of Astro-Geophysics, Department of Physics, University of Ioannina, 45110 Ioannina, Greece 

3 Section of Astrophysics, Astronomy & Mechanics Department of Physics, University of Athens, 

Panepistimiopolis 157 84, Zografos, Greece 

4 National Observatory of Athens, P.O. BOX, 20048, Thissio-11810, Athens, Greece 


We study plasma flows in NOAA Active Region (AR) 10926, observed on December 3, 2006 

by Hinode’s EUV Imaging Spectrograph (EIS). We measure the line-of-sight velocity along coronal 

loops in the Fe viii 185 ˚A, Fe x 184 ˚A, Fe xii 195 ˚A, Fe xiii 202 ˚A, and Fe xv 284 ˚A spectral 

lines and reconstruct the three dimensional (3D) plasma flow using a simple geometrical model. 

In most cases the flow is unidirectional from one footpoint to the other, resembling siphon flow. 

However there are also cases of draining motions from the loops’ top to their footpoints. The multiwavelength 

observations of the AR indicate that similar loops may show different flow patterns if 

observed in different spectral lines. We have also carried out magnetic field extrapolations using an 

SOT/Spectropolarimeter (SP) magnetogram, in order to identify magnetic field lines corresponding 

to the reconstructed 3D shapes of the loops. 

P.4.23. Stereoscopic view of a simulated magnetic element 

in Stokes-V 

N. Vitas 1 , B. Viticchié 2 and A. Vögler 3 

1 SRON - Netherlands Institute for Space Research, The Netherlands 

2 European Space Agency, ESTEC, The Netherlands 

3 Sterrekundig Instituut Utrecht, The Netherlands 


State-of-the-art 3D MHD simulations of the solar surface provide an excellent tool for studying 

small-scale magnetic elements in the photosphere and their appearance at different wavelengths and 

viewing angles. We use a snapshot from a quiet-sun simulation run (performed with the MURaM 

code, Vögler, 2005) to synthesize Stokes-V profiles of Fe I 6302 ˚Aline at a grid of heliocentric angles 

and azimuths. The computed profiles enabled us to study the stereoscopic appearance of typical 

magnetic features identified in the simulation cube and to demonstrate how Stokes-V asymmetries 

depend on a viewing angle.


P.4.24. STEREO and SDO observations of six solar jets 

A. Vourlidas 1 , S. Moschou 2 and K. Tsinganos 2,3 

1 Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA (vourlidas@nrl.navy.mil) 

2 Section of Astrophysics, Astronomy and Mechanics Department of Physics, University of Athens, 

Panepistimiopolis 157 84, Zografos, Greece (sofia paraskevi@hotmail.com) 

3 National Observatory of Athens, Lofos Nymphon, Thissio, Athens, 118 10, Greece (president@noa.gr) 


We present an analysis of recent observations of six solar jets observed at the solar limb with 

STEREO A/B and the Solar Dynamics Observatory (SDO). We construct height-time diagrams at 

all wavelengths and calculate the temporal evolution of the jets’ speed and acceleration. The first case 

is a large solar jet observed on 06/30/2010, simultaneously by STEREO & SDO in the north solar 

pole, at many wavelengths, from 171 to 304 Angstroms on 06/30/2010. It has a precursor and lasts 

in total for about 60 minutes, while the main jet reaches a height of 0.3 Rs and a maximum speed 

of about 250 km/sec. The second sample case contains a set of four solar limb jets observed 5 days 

earlier than the previous one, i.e., on 06/25/2010. All jets are observed with SDO while two of them 

are simultaneously observed with STEREO. Two jets have a precursor and last from 60 120 minutes, 

reaching heights of less than 0.2 Rs. Finally, we analyze a jet observed by STEREO on 11/12/2008 in 

174, 195, 284 and 304 Angstroms. The jet reaches a height of 0.25 Rs and a maximum speed of about 

150 km/sec. Magnetograms during the jet appearances show the corresponding magnetic topologies. 

The velocities involved are smaller than the escape speed from the sun at each radius. The results 

are preliminarily discussed in relation to possible jet formation mechanisms. 

P.4.25. Non-thermal broadening of EUV lines in flux 

emergence 

D.R. Williams 1 , E. Lee 2 , L.K. Harra 1 and G. Lapenta 2 


2 Centrum voor Plasma-Astrofysica, Katholieke Universiteit Leuven, Belgium 


Understanding the large-scale dynamics of the solar corona is a prime driver behind the use of 

spectrometers on modern solar missions; but an important mystery remains unsolved in the understanding 

of spectroscopic data. In coronal plasmas, if the ion kinetic energy distribution can be 

described by a Maxwellian (at least along the line of sight), then this Maxwellian will produce a 

Gaussian distribution of particle velocities about some mean, leading to the commonly-fit profile. 

This Gaussian has a standard deviation that is predictable from the characteristic temperature, but 

almost all EUV coronal emission lines exhibit a larger width than this prediction, even when instrumental 

effects are taken into account. This is even more true in active regions than in the quiet Sun. 

It is difficult to know how the population of electrons behaves, since we only directly measure emission 

from ions, but it cannot be ruled out that the former plays a key role in the energy transport. 

In an effort to understand the source of this line broadening, this work builds on initial findings 

that show growth of a high-energy tail of non-thermal velocities in the core of an active region, 

following a case of flux emergence. We investigate a second case of flux emergence from its early 

phase, and examine in detail the variation of this tail over several days of observation We do this 

at multiple coronal temperatures and multiple sites within the active region, and find that there is 

appreciable variation in behaviour with these variables. Crucially, we find that it is necessary to take 

kinetic effects into account if we are to explain this excess line width found throughout the solar 

corona.


Session 5 

Chromospheric and Coronal Heating 

P.5.1. Propagation of a nonlinear fast-mode MHD wave 

near a magnetic null point 

A.N. Afanasyev and A.M. Uralov 

Institute of Solar-Terrestrial Physics 


Propagation of MHD waves in an inhomogeneous medium can result in the wave energy dissipation, 

which is known to contribute into the general energy balance of the solar corona. The wave 

energy dissipation appears to occur most efficiently near magnetic null points. A portion of the wave 

is captured by the null point and the amplitude of the wave increases considerably due to the Alfvén 

speed decrease as well as the wave front convergence in the neighborhood of the null point. The 

initial linear wave transforms into a shock wave whose propagation is always accompanied by the 

energy dissipation. 

We model the propagation of a fast-mode MHD wave near a 2D magnetic null point. We consider 

both a linear wave and nonlinear one and calculate their behavior in a medium with zero sound speed 

(cold plasma case) as well as with non-zero one (warm plasma case). For this purpose we apply the 

nonlinear geometrical acoustics method based on the WKB approximation. We also calculate the 

wave amplitude, using the ray approximation and the laws of the solitary shock wave damping. 

The results obtained show the following: i) nonlinear wave passes through the null point even in 

the cold plasma case like waves propagate in warm plasma, and ii) unlike the linear cold plasma case, 

growth of the nonlinear wave amplitude is restricted, since nonlinear waves decay significantly when 

their intensities grow. 

P.5.2. Coronal model driven by photospheric observations 

Ph.-A. Bourdin 1,2 , S. Bingert 2 and H. Peter 2 

1 Kiepenheuer-Institut für Sonnenphysik, Freiburg/Germany 

2 Max Planck Institute for Solar System Research, Katlenburg-Lindau/Germany 


A 3D MHD coronal model driven by photospheric observations is setup to synthesize coronal 

emission for comparison with real observations of the coronal structure and dynamics. We start with 

a hydrostatic stratified atmosphere, apply a two hours time-series of Hinode/SOT magnetograms of a 

full active region (230*230 Mm 2 ), and drive the magnetic field by photospheric granular motions. The 

induced braiding of fieldlines leads to Ohmic dissipation that drives the dynamics of the corona and 

determines its thermal structure. Inclusion of gravity, field-aligned heat conduction, and radiative 

losses in the energy balance allows to determine the pressure in coronal structures. Coronal emission 

is synthesized using the CHIANTI atomic database. The comparison between the synthesized X-ray 

and EUV emission with the observed emission patterns and their Doppler shifts e.g. in the lines 

Fe viii, Fe xii, Fe xv, and Ca xvii will provide a crucial test for the assumed heating mechanism, 

especially the energy input distributed in space and time, e.g. Ohmic heating in nanoflares. First 

results indicate that the loop appearance and Doppler shift distribution in the model is not unlike as 

found in the observations.


P.5.3. The quiet Sun average Doppler-shift of coronal lines 

up to 2 MK 

N. Dadashi 1,2 , L. Teriaca 1 and S. K. Solanki 1,3 

1 Max-Planck-Institut fur Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany 

2 Institut fur Geophysik und extraterrestrische Physik, Technische Universitat Braunschweig, 

Mendelssohnstr. 3, D-38106 Braunschweig, Germany 

3 School of Space Research Kyung Hee University, Yongin, Gyeonggi-Do, 446-701, Korea 


The average Doppler-shift shown by spectral lines formed from the chromosphere to the corona 

reveals important information on the mass and energy balance of the solar atmosphere, providing 

an important observational constraint to any models of the solar corona. Previous spectroscopic 

observations of Vacuum UltraViolet (VUV) lines have revealed persistent average wavelength 

shift of lines formed at temperatures up to 1 MK. At higher temperatures, the behaviour was, so 

far, essentially unknown. Here we analyse combined SUMER (Solar Ultraviolet Measurements of 

Emitted Radiation)/SoHO (Solar and Heliospheric Observatory) and EIS (EUV Imaging Spectrometer)/Hinode 

observations of the quiet Sun around disk center to determine, for the first time, the 

average Doppler-shift of several spectral lines formed between 1 and 2 MK, where the largest part 

of the quiet coronal emission is formed. The measurements are based on a novel technique applied 

to EIS spectra to measure the difference in Doppler-shift between lines formed at different temperatures. 

Simultaneous wavelength-calibrated SUMER spectra allow establishing the absolute value 

at the reference temperature of T ≈ 1 MK. The average line shifts at 1 MK < T < 1.8 MK are 

modestly but clearly bluer than those observed at 1 MK. By accepting an average blue-shift of about 

(−1.8±0.6) km s −1 at 1 MK (as provided by SUMER measurements), this translates into a maximum 

Doppler-shift of (−4.4 ± 2.2) km s −1 around 1.8 MK. The measured value appears to decrease to 

about (−1.3 ± 2.6) km s −1 at the Fe xv formation temperature of 2.1 MK. The measured average 

Doppler shift between 0.01 and 2.1 MK, for which we provide here a parametrization, appears to be 

qualitatively and roughly quantitatively consistent with what foreseen by 3-D coronal models where 

heating is produced by dissipation of currents induced by photospheric motions and by reconnection 

with emerging magnetic flux. 

P.5.4. SDO/AIA EUV filter responses for the nonthermal 

distributions 

J. Dudík 1,2 , E. Dzifčáková 2 , and M. Karlický 2 

1 Dept. of Astronomy, Physics of the Earth and Meteorology, 

Faculty of Mathematics, Physics and Informatics, Comenius University, 

Mlynská dolina F2, 842 48 Bratislava, Slovakia 

2 Astronomical Institute of the Academy of Sciences of the Czech Republic, 

Fričova 298, 251 65 Ondˇrejov, Czech Republic 


Nonthermal distributions present in the solar corona and flares can change the line intensities and 

also the continuum intensity. This effects change the responses to plasma emission of all the UV, 

EUV and X-ray filters. 

We calculate the the SDO/AIA EUV filter responses for nonthermal κ-distributions. The effect of 

κ-distributions on plasma diagnostics is investigated. We also discuss the possibilities of diagnosing 

κ-distributions using SDO/AIA data only and also the effect of nonthermal distributions on the 

forward models of coronal emission.


P.5.5. An optimal multi-thermality test for solar plasma: 

application to SDO/AIA data 

C. Guennou 1 , F. Auchère 1 , K. Bocchialini 1 , S. Parenti 2 and N. Barbey 3 

1 Institut d’astrophysique Spatiale, 91405-F Orsay cedex, France 

2 Royal observatory of Belgium, avenue Circulaire 3, 1180, Brussels, Belgium 

3 CEA/SAp, Centre d’étude de Saclay, Orme des merisiers, 91191-F Gif-sur-Yvette, France 


Thermal diagnostics of the plasma have a key role in understanding many of the physical processes 

taking place in the corona. In loops for example, the isothermality or multi-thermality is still 

under debate and is a key property to understand heating mechanisms, imposing constrains on the 

theoretical models. Temperatures or Differential Emission Measures (DEMs) are derived by inverting 

spectral data, which requires a carefully analysis of the nature of the solution especially in the case of 

broadband instruments. This is by nature an ill-posed inverse problem possibly leading to multiple 

solutions. In particular, noise, uncertainties, and the shape of the contribution functions can have a 

lot of influence on the results. 

We present a comprehensive study of this spectral inverse problem, using Monte Carlo simulations 

of observed intensities in the six coronal temperature bands of the Atmospheric Imaging Assembly 

(AIA) on board the Solar Dynamics observatory (SDO). We have taken into account observations 

biases, such as shot noise, uncertainties on the AIA calibration and on the atomic data. We performed 

various isothermal and multi-thermal simulations using simple DEM models. Using a probabilistic 

approach, we quantify how much the DEM is constrained by the AIA measurements. We investigate 

to what level the AIA data are sufficient to distinguish isothermal from multi-thermal plasma. From 

this we derive an optimal quantification of the multi-thermality of the plasma. The method can be 

applied to both broad band instruments and spectrometers. We present initial results on coronal 

loops with AIA data. 

P.5.6. Numerical simulation of spicules acceleration 

N. Guerreiro 1 and M. Carlsson 1 



Observations of Hα, Ca II H and K lines on the solar limb revel the existence of structures with 

jet-like behavior, usually designated as spicules and subdivided in two types, type I and II. The 

driving mechanism for such structures remains poorly understood. Sterling et al. (1993) shed some 

light on the problem mimicking reconnection events in the chromosphere with a 1D code by injecting 

energy with different spatial and temporal distributions. They found several structures resulting from 

those injections. We follow their approach but include non-LTE cooling in strong spectral lines and 

non-equilibrium hydrogen ionization, both of which have a large effect on the dynamic behaviour. In 

this poster we report on our findings.


P.5.7. Spectropolarimetry Of The Footpoints Of A C-class 

Flare In The Chromosphere 

L. Kleint 1 and P. Judge 1 

1 HAO/NCAR, P.O. Box 3000, Boulder CO 80307, USA 


Flares are well-known solar phenomena but have rarely been imaged in high resolution polarimetry 

and even less often in the chromosphere. We observed the declining phase of a C-class flare in 

NOAA 10940 on January 29, 2007 with the IBIS instrument (0.17 ′′ /px), taking quasi-simultaneous 

spectropolarimetric images in the chromosphere (8542 ˚A) and in the photosphere (6302 ˚A). 

Only the inner wings and core of the chromospheric line are seen to brighten in IBIS, the underlying 

photosphere remaining undisturbed. TRACE images reveal the connectivity of the chromospheric 

flaring plasma to the overlying corona: IBIS fortuitously captured the chromospheric flares associated 

with both footpoints of a loop systems seen in TRACE. Our hour-long image sequence shows the 

evolution and weakening of the chromospheric flare, and reveals unresolved opposite magnetic field 

components with large velocities with respect to the average Sun. We will present high resolution 

movies of the flaring plasma seen in both footpoints of the loop system. We will discuss the implications 

of these measurements for models of the storage and release of energy for this class of small 

flare, and possible connections to the formation of the penumbra that appears later at this location. 

P.5.8. Features of time lag measurement of LOS velocity 

oscillations in solar faculae and sunspots 

N.I. Kobanov 1 , D.Y. Kolobov 1 , A.S. Kustov 1 , S.A. Chupin 1 , 

A.A. Chelpanov 1 

1 Institute of solar-terrestrial physics 


We present an investigation of line-of-sight (LOS) velocity oscillations in solar faculae and sunspots. 

For the purpose of studying of phase relations between chromosphere and photosphere oscillations, 

we obtained the time lag of the chromospheric signal relative to photospheric one for several faculae 

and sunspots in He I 10830 ˚A and Si I 10827 ˚A lines, as well as in Hα and Fe I 6559 ˚A lines. The 

time lags, measured by us, are different for different objects. The authors consider several possible 

explanations of this behavior of observed lags. 

P.5.9. Non-equilibrium ionization in 3D numerical models 

K. Olluri 1 , V. Hansteen 1 and B. Gudiksen 1 

1 Institute of Theoretical Astrophysics, University of Oslo, Norway 


The chromosphere and transition region have for the last 20 years been shown to be quite dynamic 

layers of the solar atmosphere with timescales shorter then the equilibration timescales of many of the 

ions observed in the solar atmosphere. Ions are therefore not able to reach equilibration with their 

surroundings due to the fast change in the properties of the atmosphere, where long ionization- and 

recombination times leads to ions being found far from their equilibrium temperatures. A number of 

the spectral lines we observe can therefore no longer be expected to give us any information about the 

local density or temperature. Numerical modeling is essential to interpret the observations. Modeling


of the ionization balance has earlier been done in 1D simulations, but due to many free parameters 

inherent in such modeling, led to incomplete results. Here, we used the 3D numerical code Bifrost 

together with the atomic database package DIPER to implement the rate-equations and study the 

ionization balance closer. 

We will present our implementation and a study of the C IV 1548 ˚A line, focusing on differences 

between statistical equilibrium and non-equilibrium ionization results. 

P.5.10. Prominence Differential Emission Measure: modeling 

vs. observations 

S. Parenti 1 and S.Gunár 2 and U. Anzer 3 and P. Heinzel 2 and J.-C. Vial 4 

1 Royal Observatory of Belgium, Be 

2 Astronomical Institute, Academy of Sciences of the Czech Republic, Fričova 298,25165 Ondˇrejov, Ch 

3 Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Strasse 1, 85740 Garching, De 

4 Institut d’Astrophysique Spatiale-CNRS, Université Paris Sud, Bat 121, 91405 Orsay, Fr 


One of the puzzling aspects of solar prominences is their ability to maintain the thermal stability 

for quite a long time. Their cold (< 104 K) and dense core where most lines are optically thick, is 

interfaced to the hot corona through a thin layer with a steep temperature gradient (the Prominence 

Corona Transition Region, PCTR) where the plasma becomes optically thin in most UV-EUV lines. 

Among the information needed to fully understand how the thermal equilibrium is kept, there is 

the plasma distribution with temperature (the Differential Emission Measure). Here we discuss the 

Differential Emission Measure of prominences as inferred from UV observations. We also show how 

it can be used to constrain, together with the observed H Lyman lines, a fine scale 2D prominence 

model. 

P.5.11. Catastrophic cooling of coronal loops seen in AIA/SDO 

H. Peter 1 , S. Bingert 1 and S. Kamio 1 



There is a long standing debate on episodic vs. constant heating of coronal loops. We will investigate 

the observational consequences of one aspect of this, namely the difference between normal 

cooling of a loop and catastrophic cooling. When cooling loops are observed with AIA/SDO the emission 

peaks in the AIA bands should appear according to their temperature of maximum contribution. 

However, in some cooling events the AIA bands do not brighten according to their temperature. One 

possible explanation could be that one simply looks at different structures. However, there might be 

another explanation based on catastrophic cooling. 

In the case of loss of equilibrium at the top of a loop the radiative cooling might dominate, 

reducing the temperature, and thus enhancing the radiative losses. Consequently a runaway process 

sets in, and in an event of catastrophic cooling a condensation sets in. The form of the temperature 

response function of the AIA passbands results in quite peculiar lightcurves for a catastrophically 

cooling loop: the hot channels brighten after the cool ones. This allows to distinguish between the 

normal cooling, where the heating is simply shut off, and the catastrophic cooling. 

We present 1D loop models of coronal condensations and compare this to the case when the 

heating of the loop is just stopped and the loop cools down. From this we conclude that only the 

catastrophic cooling scenario can explain the peculiar order of the brightening observed (sometimes) 

in the AIA channels.


P.5.12. High Time Resolution Observations of Hα and Hard 

X-ray Emissions of Solar Flares 

K. Radziszewski 1 , P. Rudawy 1 and K.J.H. Phillips 2 

1 Astronomical Institute of Wrocaw University, 51-622 Wrocaw, ul. Kopernika 11, Poland 

2 Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey RH5 6NT, United Kingdom 


The Hα emission of solar flare kernels and associated hard X-ray (HXR) emission are often correlated 

and similar but with time differences δt related by energy transfer mechanisms. We investigated 

the time differences with sub-second resolution between the Hα line emission observed with a Multichannel 

Subtractive Double Pass spectrograph on the Large Coronagraph and Horizontal Telescope 

at Biakow Observatory, Poland, and HXR emission recorded by the RHESSI spacecraft during several 

flares. For numerous measured Hα kernels we found a very high correlation between time variations 

of the emission at line centre and in the line wings of the Hα line and HXR (20-50 keV) flux, with 

the Hα emission following features in the HXR light curves generally by δt = 1-2 s, sometimes significantly 

longer (10-18 s). The former are consistent with energy transfer along the flaring loop legs 

by non-thermal electron beams, the latter to the passage of conduction fronts. 

P.5.13. Formation of the C II line at 1335˚A 

Bhavna Rathore 1 and Mats Carlsson 1,2 


2 Center of Mathematics for Applications, University of Oslo, P.O. Box 1053 Blindern, N-0316 Oslo, Norway 


Some of the strongest lines in the solar UV spectrum come from singly ionized carbon, at wavelengths 

of 1334˚A-1335˚A. The C II 1335˚A lines will be central observables with the NASA/SMEX 

mission Interface Region Imaging Spectrograph (IRIS). The lines are formed in the upper chromosphere/lower 

transition region and show great promise for the diagnostics of the dynamic upper 

chromosphere. 

The C II lines are formed in the optically thick, non-LTE regime and 3D numerical models are 

important for the deciphering of the diagnostic potential. To make 3D non-LTE radiative transfer 

computationally feasible it is crucial to have a model atom with as few levels as possible while retaining 

the main physical processes. 

In this work we develop such a model atom and we study the formation of the C II lines to explore 

the diagnostic potential of these lines. 

P.5.14. Comparison of Active Region chromospheric structures 

with magnetic and coronal features 

K.P. Reardon 1,2 , G. Cauzzi 1 

1 INAF - Osservatorio Astrofisico di Arcetri, Florence 

2 Astrophysics Research Centre, Queen’s University, Belfast 


We utilize the high resolution, large field of view observations of AR 11092, described in an 

accompanying poster, to compare the chromospheric structure observed in the core of the Hα and CaII 

854.2 nm lines to both SDO/HMI magnetic maps and extrapolations, and coronal structure observed 

with SDO/AIA. In particular, we exploit the high spatial resolution and large spatial coverage of 

the chromospheric data to define and trace the extension of the fibrils visible in the core of the two 

chromospheric lines.


P.5.15. The most comprehensive observations of the 

chromosphere of an Active Region 

K. P. Reardon 1,2 , G. Cauzzi 1 

1 INAF - Osservatorio Astrofisico di Arcetri, Florence 

2 Astrophysics Research Center, Queen’s University, Belfast 


We present comprehensive observations of the chromosphere of AR NOAA 11092, obtained on August 

3, 2010 at high spatial and spectral resolution. The IBIS imaging spectrometer at the DST/NSO 

was used in a mosaic mode to cover the active region and surrounding areas over a large field of view of 

4 ′ x 4 ′ , while maintaining a spatial resolution close to 0.2 ′′ and full spectral coverage of chromospheric 

Hα, CaII 854.2 nm, and He I D3, as well as photospheric FeI 543.4 nm. 

Line intensities, shifts and widths are presented for the various structures within the region, 

and compared with simultaneous SDO/AIA and HMI images and magnetograms. The wealth of 

information is suited to a variety of statistical studies of both active and quieter Sun, including 

chromospheric fibrillar structures and their relationship with the corona; heating in and around 

magnetic areas; magnetic topology over the AR size. 

The spectral data will be made available to the community in a readily usable form. 

P.5.16. On-disc counterparts of type II spicules: Simultaneous 

observations of RBEs in the Ca II 854.2 nm and Hα lines 

D.H. Sekse 1 , L. Rouppe van der Voort 1 and B. de Pontieu 2 


2 Lockheed Martin Solar and Astrophysics Lab, Org. ADBS, Bldg. 252, 3251 Hanover Street Palo Alto, CA 94304 USA 


Recently, spicules were found to exist in two different types. A new class of so-called type II spicules 

was discovered at the solar limb with the Solar Optical Telescope onboard the Hinode spacecraft. 

These type II spicules have also been linked with on-disc observations of Rapid Blue-shifted Excursions 

(RBEs) in the Hα and Ca II 854.2 nm lines. Here we analyse observations with the CRisp Imaging 

SpectroPolarimeter (CRISP) at the Swedish Solar Telescope (SST) on La Palma. The observational 

program was optimised for detection of RBEs in both the Hα and Ca II 854.2 nm lines at high temporal 

cadence. In this study we analyse a number of high-quality time sequences of different targets and 

expand on the RBE statistics presented in Rouppe van der Voort et al. 2009. Furthermore, we 

focus on the temporal evolution of RBEs and the differences between the Hα and Ca II 854.2 nm 

observations.


P.5.17. Nonlinear plasma wave interactions in the solar corona 

F. Spanier 1 and R. Vainio 2 

1 Universität Wrzburg 

Lehrstuhl für Astronomie 

Emil-Fischer-Str. 31 

D-97074 Würzburg 

2 Helsinki University 


The interaction of plasma waves plays a crucial role in the dynamics of weakly turbulent plasmas. 

So far the interaction of non-dispersive waves has been studied. In this talk the theory is extended 

to dispersive waves. It is well known that dispersive waves may be found in the solar corona, where 

they contribute to the heating of the corona. Here the possible interactions in the solar corona are 

described and the interaction rates are derived in the dispersive wave limit. 

Additionally the connection to the emission of radio waves in bursts is discussed. Wave-wave 

interaction is regarded as a possible emission mechanism. 

P.5.18. EIS/Hinode Observations of MHD Mode Coupling in 

the Solar Atmosphere 

A.K. Srivastava 1 , T.V. Zaqarashvili 2 , B.N. Dwivedi 3 and Mukul Kumar 3 

1 Aryabhatta Research Institute of Observational Sciences (ARIES), Manora Peak, Nainital-263 129, India. 

2 Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria. 

3 Department of Applied Physics, Institute of Technology, Banaras Hindu University, Varanasi-221005, India. 


It is well known that the photospheric acoustic power peaks around 5.0 min, which is generated 

due to sub-photospheric dynamics. Leakage of these oscillations into upper solar atmosphere may 

be significant to understand the dynamics and heating of solar plasma. However, its leakage into 

the solar atmosphere is still under debate both in theory and observations. The longitudinal waves 

with the period of ∼ 5.0 min may resonantly transfer energy into other wave modes in the lower 

solar atmosphere where plasma beta tends to unity. Using Hinode/EIS observations, we find that 

intensity oscillations in He II 256.32 ˚A show temporal decay during the total span of the observation 

above an EUV bright point. This may be a most likely observational signature of acoustic wave 

damping in the upper chromosphere. On the other hand, the intensity oscillations in Fe XII 195.12 ˚A 

show amplification, which may be a signature of mode-coupling and resonant energy conversion from 

transverse magnetohydrodynamic (MHD) waves of the double period into the observed acoustic waves 

in the lower solar atmosphere. We discuss the physical implications of these unique observations in 

light of various theoretical models related to wave-wave interaction.


P.5.19. High-frequency Waves in Numerical Simulations of 

the Solar Atmosphere 

Th. Straus 1 , B. Fleck 2 and G. Severino 1 

1 INAF/Osservatorio di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy 

2 ESA Science Operations Department, c/o NASA/GSFC, Greenbelt, MD, USA 


We investigate the excitation processes, propagation characteristics, and energy transport of highfrequency 

waves in the solar atmosphere with the help of high-resolution 3D radiation-hydrodynamics 

simulations. Time series of synthetic spectra of four photospheric Fraunhofer lines (Fe 6302, Fe 6301, 

Fe 6173, Ni 6768) from these simulations are analyzed in order to evaluate the diagnostic power of 

spectroscopic observations. 

P.5.20. Coronal temperature during total solar eclipses 

at the extended solar minimum of solar cycle 23 

I.M. Strikis 1,2,3 , A. Kouloumvakos 3,4 and George Xystouris 3,4 

1 Hellenic Amateur Astronomy Association, Greece. 

2 Elizabeth Observatory of Athens, Greece. 

3 H.E.L.I.O.S. Observing Team, Greece. 

4 Department of Physics, University of Athens, Greece. 


Coronal temperature diagnostics are essential for the general understanding of coronal properties 

during a solar cycle. With spectroscopic measurements during total solar eclipses, temperature can be 

derived from the forbidden iron lines ratio. We will present our results of temperature variations from 

the measurements of FeXIV/FeX line ratio during 2006-2010 total solar eclipses. Also a correlation 

of temperature with sunspot number, radio flux and flare occurrence will be presented. 

P.5.21. Nanoflare-heated coronal loop models 

R. Susino 1 , D. Spadaro 1 , A.C. Lanzafame 1,2 and A. F. Lanza 1 

1 INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, I-95123, Catania, Italy 

2 Dipartimento di Fisica e Astronomia - Sez. Astrofisica, Università di Catania, via S. Sofia 78, 

I-95123, Catania, Italy 


The problem of the heating of the solar corona is one of the major unresolved issues in solar 

physics. Among the various still-open points, one is related to the characterisation of the temporal 

and spatial properties of the heating mechanisms that give rise to the million-degree hot coronal 

loops. 

Several efforts have been made to address this point, but presently is not yet clear whether loops 

are heated steadily or dynamically, and if the heating is concentrated somewhere within them or it 

is uniform along their axes. 

Recent TRACE and SOHO observations show that a large number of coronal loops have physical 

properties in contrast with those predicted by hydrostatic models. For warm loops (∼ 1 MK), 

observed features include high electron densities, unstructured temperature and emission distributions 

along loop axes, and lifetimes longer than a characteristic cooling time.


One of the most appealing theories proposed to explain these observational evidences states that 

coronal loops are collections of elemental magnetic flux tubes with sub-resolution cross-sectional 

dimension (strands) which are individually heated by small-scale energy pulses (nanoflares) that 

originate from magnetic interactions of the chromospheric footpoints of the loops. 

In this framework, we examine whether multi-strand models of coronal loops with steady or impulsive 

heating are able to reproduce the density structure and the emission properties of observed 

loops. In particular, our simulations are based on coronal heating that is localised at the chromospheric 

footpoints of the loops and exponentially decreases with height. We explore the impact of 

several model parameters – such as the nanoflare magnitude and duration, the nanoflare cadence time, 

the total number of strands bundled in the multi-strand, and the time delay between the onset of the 

heating in the first strand and that in the last one – on some plasma-related observable quantities – 

e.g., the differential emission measure (DEM), the density excess, the loop lifetimes as measured in 

the 171 ˚A and 195 ˚A filters of TRACE, and the Doppler shifts of different EUV spectral lines. 

Our results show that a unique heating regime is unable to reproduce all the observational features 

of warm coronal loops, but high-frequency impulsive heating appears to be the most suitable in that 

it successfully explains certain aspects of the observations, notably the density excess, the uniform 

spatial distribution of the emission and the overall behaviour of the light curves in the EUV TRACE 

passbands. In addition, we find that heating conditions in which the nanoflare cadence time is sensibly 

shorter than the plasma cooling time can reproduce the pronounced DEM peak as observed in active 

regions. On the other hand, cadence times longer than the plasma cooling time yield the typical 

DEM structure as observed in the quiet Sun regions. 

P.5.22. Testing coronal plasma diagnostics using 3D MHD 

models of the solar atmosphere 

P. Testa 1 , J. Martinez-Sykora 2,3 , V. Hansteen 3 , B. De Pontieu 2 , 

and M. Carlsson 3 

1 Harvard-Smithsonian Center for Astrophysics 

2 Lockheed Martin Solar & Astrophysics Lab 

3 Institute of theoretical astrophysics, University of Oslo 


We synthesize coronal images and spectra from realistic 3D radiative MHD simulations obtained 

from the state-of-the-art Bifrost code, and explore how well they reproduce coronal observations 

with SDO/AIA and Hinode/EIS and XRT. We apply standard diagnostic techniques (e.g., density, 

temperature, abundance diagnostics) to the synthetic observations and investigate how accurately the 

derived physical information matches the plasma parameters of the model. We discuss the limitations 

of the diagnostics and their implications, also in light of the parameters of the models. 

P.5.23. The quest for on-disc high velocity spicules 

K. Tziotziou 1,2 , G. Tsiropoula 2 , I. Kontogiannis 2 and G. Cauzzi 3 

1 Research Center of Astronomy and Applied Mathematics, Academy of Athens, GR-11527, Greece 

2 Institute for Space Applications and Remote Sensing, National Observatory of Athens, 

Lofos Koufos, Palea Penteli 15236, Greece 

3 INAF Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze, Italy 


We study mottles/spicules seen in high resolution images obtained on 15 March 2007 with the 

imaging spectrometer IBIS at the Dunn Solar Telescope that cover a sizable quiet-Sun field-of-view, 

close to the disc center, including large areas of quiet-Sun network. A sequence of 192 two-dimensional


spectral images is used, sampling the Hα line at 22 wavelength positions around the line core with a 

constant spectral sampling interval of 0.01 nm and a temporal cadence of 15.4 seconds. 

This extended sampling of the Hα line wings, up to ±1 ˚A from its core, permits us to search 

for on-disc counterparts of high-velocity mottles/spicules that have been reported at the solar limb 

over the past years based on high resolution Hinode observations. For this reason we study the 

morphology and dynamic behavior of dark mottles/spicules as seen in different wavelengths of the 

Hα line profile that possibly reflect the existence of a high line-of-sight velocity component on the 

Hα profile. Furthermore, line inversion techniques are used in order to determine some physical 

properties of the observed dark mottles/spicules such as their velocity, optical thickness and source 

function. We discuss the obtained global properties of on-disc mottles/spicules as well as the spatial 

and temporal evolution and compare them with the respective properties and dynamics of on-limb 

spicules reported in recent literature. 

P.5.24. Response of the corona to different heating 

mechanisms 

T. van Wettum 1 , S. Bingert 1 and H. Peter 1 

1 Max-Planck-Institut für Sonnensystemforschung(MPS), 37191 Katlenburg-Lindau, Germany 


We present a series of 3D MHD models of the solar corona to distinguish between different 

heating mechanisms for the deposition of energy in time and space. In these numerical experiments 

we describe the corona above an active region driven by photospheric motions. When solving the 3D 

MHD problem we put special emphasis on the energy equation, accounting for radiative losses and 

heat conduction. Only this provides the necessary physics to get a realistic thermal structure in the 

corona, i.e., temperature and density. Moreover, this procedure allows us to synthesize EUV emission 

from the numerical experiments that can be compared to real observations. To investigate the relative 

merits of different heating mechanism, we employ different parametrizations of the heating function, 

e.g., for Ohmic heating or for turbulent diffusion. The energy input is implemented as power laws 

of magnetic field, density temperature, etc, or a mixture of these. Through this we can investigate 

different distributions of the energy input in time and space. From the results of the MHD experiments 

we then calculate the coronal response in the form of synthesized maps in EUV intensity and Doppler 

shift. The comparison between synthesized observations for different models and real observations, 

in terms of structure and dynamics, provide information to distinguish between different heating 

mechanisms employed. 

P.5.25. Heating of Spicules as observed from Imagers and 

Spectrometers 

K. Vanninathan 1 , M.S. Madjarska 1 and J.G. Doyle 1 

1 Armagh Observatory, College Hill, Armagh BT61 9DG, N. Ireland 


The contribution to coronal heating by spicules is a long standing issue. The discovery of very 

long, thin spicules (the so called Type II) has revived interests in this field. These dynamic jet-like 

features which dominate coronal hole regions have been reported to be seen in coronal line filters of 

AIA/SDO. Our analysis of similar features using spectrometers (SUMER/SoHO and EIS/Hinode) 

has revealed contrary results. We find that these long, thin spicules group together to form larger 

jet-like structures seen as single large jet in lower resolution instruments. Despite their grand size, we 

found that these dynamic features do not reach temperatures above 300 000 K. We suggest that this


discrepancy in results is due to the difference in interpretation of observations obtained from an imager 

and a spectrometer. Although the AIA 171 A channel is dominated by the hot Fe IX emission it also 

contains an abundance of cooler O V and VI emissions. Thus in the absence of hot plasma the cooler 

lines will have significant contribution to the emission in the AIA 171 passband. Without careful 

spectroscopic studies of the response of the AIA channels, this data can be easily mis-interpreted. 

We intend to further investigate the response of the AIA passbands using DEMs of transient events 

like spicules from SUMER observations with the help of Chianti and ADAS databases. 

P.5.26. The role of leakage in the turbulent heating of 

coronal loop 

A. Verdini 1 , R. Grappin 2 and M. Velli 3 

1 SIDC, Observatoire Royal de Belgique 

2 LPP, Ecole Polytechnique. LUTH, Observatoire de Paris 

3 Dip. di Astronomia, Univ. di Firenze. JPL, California institute of Technology 


The heating of active-regions loop by waves and turbulence is usually carried out neglecting the 

feedback of coronal dynamics onto the chromosphere and photosphere. Indeed the long leakage 

timescale (> 10 5 s) is thought to play a minor role compared to the average dissipation timescale (of 

the order of 10 3 −10 4 s) However, for typical active region loops, turbulence in the corona is in a weak 

regime, producing a very intermittent dissipation, in other words, the dissipation time may be larger 

than the leakage time which can not be neglected anymore. Using a simple loop model and numerical 

simulations of the simplified RMHD equations (hybrid shell model) we extend previous works on 

turbulent heating of coronal loops including the coronal feedback on the chromosphere. We show 

how leakage, changing the coronal injection spectrum and limiting the coronal energy accumulation, 

influences the properties of turbulence (weak/strong) and so the scaling laws for energy, heating, and 

dissipation timescale vs loop parameters. We find that passing from strong to weak turbulence the 

coronal dissipation per unit mass decreases (contrary to the line-tied case for which it increases) and 

discuss the implications for coronal heating. 

P.5.27. Damping of MHD waves in solar partially ionized 

plasmas: effects of multi-fluid approach 

T.V. Zaqarashvili 1 , M.L. Khodachenko 1 and H.O. Rucker 1 

1 Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria 


Partially ionized plasma is usually described by a single-fluid approach, where the ion-neutral 

collision effects are expressed by Cowling conductivity in the induction equation. However, the singlefluid 

approach is not valid for time-scales less than ion-neutral collision time. For these time-scales the 

two-fluid description is the better approximation. We derive the dynamics of magnetohydrodynamic 

waves in multi-fluid partially ionized plasmas and compare the results with those obtained under 

single-fluid description. Multi-fluid magnetohydrodynamic (MHD) equations are used, where ionelectron 

plasma and neutral particles are considered as separate fluids. Dispersion relations of linear 

magnetohydrodynamic waves are derived for the simplest case of homogeneous medium. Frequencies 

and damping rates of waves are obtained for different parameters of background plasma. We found 

that two- and single-fluid descriptions give similar results for low-frequency waves. However, the 

dynamics of MHD waves in the two-fluid approach is significantly changed when the wave frequency


becomes comparable with or higher than the ion-neutral collision frequency. Alfvén and fast magnetoacoustic 

waves attain their maximum damping rate at particular frequencies in the wave spectrum. 

The damping rates are reduced for the higher frequency waves. Some results of the single-fluid 

description should be revised in future such as the damping of high-frequency Alfvén waves in the 

solar chromosphere due to ion-neutral collisions.


Session 6 

Transient Activity and Seismology of the Solar Atmosphere 

P.6.1. Magnetic field variations and HXR emissions: a 

comparative analysis for the first two X-class flares of the 24th 

solar cycle 

J.D. Alvarado 1 , J.C. Buitrago 1 , J.C. Martínez 2 , C. Lindsey 3 , H. Hudson 2 

and B. Calvo 1 

1 OAN - Universidad Nacional de Colombia 

2 SSL - University of California Berkeley 

3 NorthWest Research Associates - Colorado Research Associates Division 


Multi-wavelength studies of energetic solar flares with seismic emissions have revealed interesting 

common features among them. We develop a comparative study for the first seismically active flare 

of the 24th solar cycle (SOL2011-02-15T01:52 X2.2) detected by HMI/SDO (Kosovichev, 2011) and 

the second X-class flaring event (SOL2011-03-09T23:22 X1.5) of this period, which appears to be a 

non-seismically energetic flare. The first part of the analysis consists of a pixel-by-pixel light-curve 

characterization of the fluctuations of the photospheric line-of-sight magnetic field based on HMI 

data. This shows strong differences between the behavior of the magnetic field near the seismic 

sources in the two flares. For the seismically active flare a persistent change in the field appears; 

by comparison pseudo sources - regions of an apparent strong change in the line-of-sight magnetic 

field - appear in the non-seismic flare. We compare the locations of the HXR emission kernels and 

the correlations between them with the sources (X2.2 flare) and pseudo-sources (X1.5 flare) of the 

photospheric magnetic changes. For context we used HXR RHESSI data to locate these emission 

kernels and check if there is any relation between them and the spatial location of the transient 

longitudinal magnetic field changes in the photospheric region where these two flares took place. 

P.6.2. On the dispersion and scattering of MHD waves by 

longitudinally stratified flux tubes 

J. Andries 1 , and P.S. Cally 2 

1 Centrum voor Plasma Astrofysica, Katholieke Universiteit Leuven, Celestijnenlaan 200B, B-3001, Leuven, Belgium 

2 Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, 3800, Victoria, Australia 


We provide a fairly general analytic theory for the dispersion and scattering of magnetohydrodynamic 

waves by longitudinally stratified flux tubes. The theory provides a common framework for, 

and synthesis of, many previous studies of flux tube oscillations that were carried out under various 

simplifying assumptions. The present theory focuses at making only a minimal amount of assumptions 

and removing many unnecessary assumptions. As a result it thus provides an analytical treatment of 

several generalizations of existing tube oscillation models. The most important practical cases are: 

inclusion of plasma pressure and possibly buoyancy effects in models of straight non-diverging tubes 

such as applied in coronal seismology, and, relaxation of the ‘thin tube’ approximation in oscillation 

models of diverging tubes, as applied both in the context of p-mode scattering and coronal seismology. 

In particular it illustrates the unifying theoretical framework underlying both the description of 

waves scattered by flux tubes and the dispersion of waves carried along flux tubes.


P.6.3. Time damping of non-adiabatic magnetohydrodynamic 

waves in a partially ionised prominence medium: Effect of a 

background flow 

S. Barcel 1 , M. Carbonell 2 and J. L. Ballester 1 

1 Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain 

2 Departament de Matemtiques i Informtica, Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain 


The simultaneous occurrence of flows and time damped small-amplitude oscillations in solar prominences 

is a common phenomenon. These oscillations are mostly interpreted in terms of magnetohydrodynamic 

(MHD) waves. We study the time damping of linear non-adiabatic MHD waves in a 

flowing partially ionised plasma with prominence-like physical conditions. Considering non-adiabatic 

single fluid equations for a partially ionised hydrogen plasma, we have solved our dispersion relations 

for the complex frequency, ω, and we have analysed the behavior of the period, damping time and 

the ratio of the damping time to the period, versus the real wavenumber k, for Alfvén, fast, slow, and 

thermal waves. While in the case without flow there is a critical wavenumber at which the period 

of Alfvén and fast waves goes to infinite, when a flow is present two different critical wavenumbers 

appear. The smaller wavenumber depends on the flow speed and causes the period of the high-period 

branch to go to infinite. When the second critical wavenumber is attained the period of both branches 

become equal. In general, the time damping of Alfvén and fast waves is dominated by resistive effects, 

and its damping ratio is very inefficient when compared to observations. The damping of slow and 

thermal waves is basically dominated by non-adiabatic effects, and for slow waves it is possible to 

obtain a damping ratio close to observations, although it would correspond to long period oscillations 

with large damping times not often observed. The consideration of a structured medium produces 

new features such as the apparition of four critical wavenumbers for Alfvén waves, and one critical 

wavenumber for slow waves. For fast waves, constrained propagation substantially improves, within 

the range of observed wavelengths, the ratio of the damping time to period. The presence of a 

background flow in a partially ionised plasma gives place to new interesting features when the time 

damping of MHD waves is studied. In general, the results point out that ion-neutral collisions are 

an inefficient mechanism to explain the observed time damping of prominence oscillations if they are 

produced by Alfvén and fast waves. If the oscillations are produced by slow waves, only long period 

oscillations with large damping times produce damping ratios in agreement with observations. 

P.6.4. Metric Radio Bursts and Fine Structures in the 

1998–2010 Period 

C. Bouratzis 1 , A. Hillaris 1 , C. Alissandrakis 2 , P. Preka-Papadema 1 , X. 

Moussas 1 , C. Caroubalos 3 , P. Tsitsipis 4 , and A. Kontogeorgos 4 

1 Department of Physics, University of Athens, Zografos (Athens), 15783, Greece 

2 Department of Physics, University of Ioannina, 45110 Ioannina, Greece 

3 Department of Informatics, University of Athens, 15783 Athens, Greece 

4 Department of Electronics, Technological Educational Institute of Lamia, Lamia, 35100, Greece 


We analyzed 61 metric Type IV radio bursts recorded by the Acousto–Optic (SAO) receiver of 

the ARTEMIS–IV radiospectrograph in the 270–450 MHz range from 1998 to 2010. The high time 

resolution (10 ms) and sensitivity of the receiver made possible a detailed analysis of the fine structure 

embedded in the events. In this work we present the main observational characteristic of this fine 

structure and we compare our results with previous works.


P.6.5. Curved Coronal Rays as Indicators of the Solar 

Environment 

B.P. Filippov 

Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, 

Russian Academy of Sciences, Troitsk Moscow Region 142190 Russia 


Thin coronal rays sometimes look curved during their passage above the solar polar regions due to 

the solar rotation. The rays are always convex in the direction of their motion along the position angle 

in accordance with the Parker’s idea on the spiral interplanetary magnetic field formation. However, 

preliminary measurements of deviation from radial direction is not exactly consistent with the theory. 

Thin coronal rays located several tens of degrees away from a propagating CME are deflected and 

become temporarily curved. The hump of the ray moves along it outwards as a kink perturbation. 

Distant streamer deflections are often assumed to be indirect evidence of shocks generated by fast 

CMEs in the corona. However, there are other reasons for the streamer deflections. The coronal ray 

deflection can be interpreted as the influence of the magnetic field of a moving flux rope related to 

a CME. The motion of a large-scale flux rope away from the Sun creates changes in the structure of 

surrounding field lines, which are similar to the kink propagation along coronal rays. Careful analysis 

of these events could give us valuable information about coronal plasma, for example, an estimation 

of Alfvén speed. 

P.6.6. Understanding the nature of pulsations in flares 

using RHESSI 

A. R. Inglis 1 , B. R. Dennis 1 



RHESSI is one of the primary instruments used in the study of quasi-periodic pulsations in solar 

flare light curves, the nature of which is still the subject of debate. Its high temporal cadence and 

wide coverage of the X-ray regime allows the detection of many impulsive flaring events, key to our 

understanding of flare processes. 

The detection of periodic behaviour with RHESSI is sometimes complicated by its own rotation 

and nutation motions. On rare occassions, the 40s nutation period of the spacecraft is shown to 

manifest itself in the X-ray lightcurves, resulting in false detections of pulsations. We show examples 

of this behaviour on 2004 November 4, and 2004 November 6, but also how this can be accounted for 

using dynamic corrections of livetime, data gaps and collimating grid transmission. 

The spatial resolution of RHESSI also allows us to study the motion of hard X-ray footpoints 

during flaring pulsations. This behaviour is key to understanding whether such pulsations can be 

explained via MHD wave phenomena, or whether pulsations are instead a signature of intermittent 

magnetic reconnection. For certain wave models, we might expect discontinuous motion of X-ray 

footpoints along two-ribbon arcades, while magnetic reconnection regimes impose no such constraints. 

We test for this behaviour during the flares of 2002 November 9 and 2005 January 19 by correlating 

hard X-ray footpoint separation to the pulse intervals. Finally, we explore the new potential of 

RHESSI used in tandem with the enhanced imaging capabilities of SDO/AIA, where pulsations can 

finally be studied in the context of flare arcade evolution.


P.6.7. Wave propagation in a solar network region through 

phase difference analysis 


1 National Observatory of Athens, Institute for Space Applications and Remote Sensing, Lofos Koufos, 15236 Palea 

Penteli, Greece 




We investigate wave propagation in a solar network region using a set of multi-wavelength observations 

obtained during a coordinated campaign. The observations were acquired by the ground-based 

Dutch Open Telescope (DOT), the Michelson Doppler Imager (MDI) on-board SOHO and the UV 

filters of the Transition Region and Coronal Explorer (TRACE). A large height range in the solar 

atmosphere, from the deep photosphere to the upper chromosphere is covered by these instruments. 

Wavelet analysis is used to calculate coherence and phase differences between oscillations observed 

in the different atmospheric layers. The aim of our work is to find indications or evidences of the 

presence of the various MHD modes described in theory for the solar plasma and determine the effect 

of the magnetic field in wave propagation. 

P.6.8. Study of spicules observed in the CaII H and Hα 

lines by Hinode/SOT 


1 National Observatory of Athens, Institute for Space Applications and Remote Sensing, Lofos Koufos, 

15236 Palea Penteli, Greece 




We use a dataset of simultaneous image sequences of the SW solar limb obtained by Hinode/SOT 

with the Ca II H filter, as well as in Hα±0.2 ˚A. The high temporal and spatial resolution allows 

us to study the structure and dynamics of spicules seen at the different filters. Individual spicules 

have been selected and intensity and velocity distributions at different heights along their central 

axes are examined along with transversal fluctuations. Furthermore, we examine the morphology 

and temporal variation of several other limb structures. 

P.6.9. Spatial structure of the source of quasi-periodic 

pulsations with a drifting period 

E.G. Kupriyanova 1 , V.F. Melnikov 1,2 

1 Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, 196140, Saint-Petersburg, Russia 

2 Purple Mountain Observatory of CAS, 210008, Nanjing, China 


Quasi-periodic pulsations (QPP) with the period drifting from P ≈ 20 to P ≈ 30 s were detected in 

a single flaring loop using data on the integrated radio flux measured with Nobeyama Radioheliograph 

(see Kupriyanova et al. Sol.Phys. 2010, 267, 329). In this paper, we concentrate on a detailed study 

of the spatial structure of the pulsations with methods of correlation, Fourier and wavelet analysis.


The main finding is that there exist two spatially well separated sources of the QPP with relatively 

stable periods of 20 s and 30 s. The source of QPP with period P ≈ 30 s has its maximum amplitude 

in the inner region of the loop, between the footpoints. The source of QPP with period P ≈ 20 s is 

localized at the periphery of the loop, mainly in the outer parts of the footpoints. Spectral amplitudes 

of these sources change over time differently. It is shown that the apparent drift of the period found 

from the analysis of the signal integrated over the whole flaring loop is due to a gradual redistribution 

of oscillation intensity from a peripheral source to an internal source. Possible reasons for the found 

differences in the spatial distribution of the amplitudes of the two spectral components are discussed. 

In particular, a possibility of the simultaneous generation of QPP at the fundamental and second 

harmonics of the sausage mode is considered. 

P.6.10. How do we observe the acoustic sources of the Sun? 

G. Severino 1 , Th. Straus 1 M. Oliviero 1 , M. Steffen 2 and B. Fleck 3 

1 INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy 

2 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, Potsdam, Germany 

3 ESA Science Operations Dep., c/o NASA GSFC, Mailcode 671.1, Greenbelt, MD 20771, USA 


We present new interpretations for : i) the variation of the positive intensity (I) - velocity (V ) 

phase difference of the p-modes close to the base of photosphere; and ii) the plateau-interridge regime 

of negative I − V phases, where low-frequency p-modes are embedded, first observed by Deubner et 

al. 1990. These interpretations are based on a model of the observed intensity fluctuation which 

includes the effects that the steep photospheric temperature gradient and the opacity have on the 

evanescent oscillations, as discussed by Severino et al. 2008 and 2010. In order to make the model 

more sound, a treatment of non-adiabatic effects was added in the form of the Newtonian cooling 

approximation. 

We also discuss the consequences of our model on the method for fitting power and cross-spectra 

of p-modes developed by Severino et al. 2001, and give new support to the following scenario: The 

acoustic sources that excite modes in their evanescent region generate a coherent background of 

downward (and upward) evanescent oscillations which is observed as the plateau-interridge regime of 

negative I − V phases extending in frequency from the Lamb wave line up to a curve near parallel to 

ω ≈ 3.5 mHz. 

P.6.11. Resonant Absorption of Propagating MHD Waves 

in Partially Ionized Solar Plasmas 

R. Soler 1 , R. Oliver 2 , J. L. Ballester 2 and M. Goossens 1 

1 Katholieke Universiteit Leuven, Belgium 

2 Universitat de les Illes Balears, Spain 


Ubiquitous propagating magnetohydrodynamic (MHD) kink waves have been recently observed in 

the solar corona using the Coronal Multi-Channel Polarimeter (CoMP). Resonant absorption, caused 

by plasma inhomogeneity in the transverse direction to the magnetic field, is a natural damping 

mechanism for MHD kink waves. In fully ionized, coronal plasmas Terradas, Goossens, & Verth 

(2010, TGV) obtained that the damping length due to resonant absorption is inversely proportional 

to the wave frequency. This result has been shown to be consistent with CoMP data. However, apart 

from observations in coronal loops, propagating kink waves have also been observed in chromospheric 

spicules and in thin threads of solar prominences. Due to their relatively cool temperature, chromospheric 

and prominence plasmas are only partially ionized. This fact raises the relevant question


on whether the damping length remains inversely proportional to the frequency when the plasma is 

partially ionized or, on the contrary, this dependence is modified by the effect of collisions between 

the different species. Here, we study for the first time the spatial damping of resonant MHD kink 

waves in partially ionized magnetic flux tubes in the single-fluid approximation. We use approximate 

analytical theory along with full numerical computations. We find that kink waves are damped 

by both resonant absorption and ion-neutral collisions. The contribution of resonant absorption to 

the damping length is inversely proportional to the frequency as in the fully ionized case, while the 

contribution of ion-neutral collisions is inversely proportional to the square of the frequency. This 

result means that high-frequency waves are more efficiently damped by ion-neutral collisions than by 

resonant absorption. Nevertheless, for frequencies typically observed in spicules and prominences the 

effect of resonant absorption dominates and the expressions derived by TGV remain approximately 

valid. Preliminary results using the multi-fluid description of the plasma instead of the single-fluid 

approximation are given. Finally, implications for plasma heating are also discussed. 

P.6.12. Temperature stratification and spatial structure 

of the EUV waves above sunspots 

R.A. Sych 1 , V.M. Nakariakov 2 , S.A. Anfinogentov 3 and Y. Yan 1 


2 University of Warwick, Coventry, UK 

3 Institute of Solar-Terrestrial Physics, P.O.Box 4026, Irkutsk, Russia 


The study of wave and oscillatory processes above the sunspot NOAA 1131 on the 8th of December 

2010 in the EUV band with use the SDO/AIA are presented. The spatial structure of the sources of 

the main oscillating modes was identified for the first time at 10 different observational wavelengths. 

At the photospheric heights the 5.6 mHz oscillation source has a circular shape, filling in the umbra. In 

the chromosphere this oscillations are seen as waves propagating radially up to the umbra-penumbra 

boundary. The wave fronts have a spiral shape. The centre of the spiral located near the centre of 

the sunspot. In the corona we observe the formation of radially extended fine structures over the 

penumbra, which coincide with the footpoints of coronal magnetic flux tubes. Individual tubes are 

characterised by specific frequencies of the propagating waves. The sources of longer-period (more 5.6 

mHz) oscillations have the ring shape where the oscillation power has a radially patchy distribution. 

At the photospheric height, the value of the dominating spectral peak changes rather abruptly. In the 

chromosphere, oscillation frequencies decrease with the distance from the sunspot centre gradually 

from 5.6 mHz in the umbra up to 0.8 mHz in the penumbra. 

The formation of multi-peaked structure near the 3-min main peak in the Fourier spectrum may be 

explained in terms of the frequency drift of the waves and the presence of multiple spatially separated 

sources of the oscillations and their stratification in the frequency range. 

A possible interpretation of the obtained results could be connected with the model of twist of 

the spaghetti-like magnetic flux tubes, emerging from the sub-photospheric regions. The flux tubes 

act as wave-guides of the slow magnetoacoustic waves, responsible for the observed oscillations.


P.6.13. Sub-arcsecond VAULT H-Lyα observations and 

multiwavelength analysis of an active region filament 

J.-C. Vial 1 , A. Philippon 1 , K. Olivier 1 and A. Vourlidas 2 

1 Institut d’Astrophysique Spatiale, Université Paris-Sud and CNRS, 91405 Orsay, France 

2 Naval Research Laboratory, 4555 Overlook avenue SW, Washington, DC 20375, USA 


The H-Lyα line emitted by filaments (or prominences) has received much attention recently from 

spectroscopic measurements with SUMER on SOHO and high resolution imaging either obtained with 

VAULT or planned with the HRI-EUI instrument on Solar Orbiter. Because of its very large opacity 

and its formation at about 20 000 K, this line is ideally suited for investigating the filament’s coronal 

environment, perturbed by either cool absorbing material (in the EUV) or the so-called emissivity 

blocking. We present a thorough study of an active region filament observed on June 14th, 2002 with 

VAULT along with associated space and ground-based observatories (Hα and magnetic field (BBSO), 

and EUV lines (EIT and TRACE)). Spine and barbs are well identified in H-Lyα with the help of Hα 

images and magnetograms. Fine elongated structuring was found at scales of about one arcsecond 

in the thick H-Lyα line. The filament intensity normalized to the intensity in the (active) region it 

is embedded in, is about 0.3 in H-Lyα, the lowest value as compared to other lines. The comparison 

of cuts in different lines across the filament shows evidence of strong absorption and consequently of 

cool plasma well around the Hα filament. 

P.6.14. Statistical Analysis of Langmuir Waves Associated 

with Type III Radio Bursts 

S. Vidojević 1,2 , A. Zaslavsky 3 , M. Maksimovic 1 , M. Draˇzić 4 , 

O. Atanacković 2 

1 LESIA Observatoire de Paris, Section de Meudon, 5, place Jules Janssen, Meudon Cedex, 92195 France 

2 Department of Astronomy, Faculty of Mathematics, University of Belgrade, Studentski trg 16, 

11000 Belgrade, Serbia 

3 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States 

4 Department of Numerical Mathematics and Optimization, Faculty of Mathematics, University of Belgrade, 

Studentski trg 16, 11000 Belgrade, Serbia 


Radio observations of the waves in a range of 4 - 256 kHz from the WAVES experiment onboard 

the WIND spacecraft have been statistically analyzed. A subset of 36 events with Langmuir waves 

and type III bursts occurred at the same time, has been selected. After background has been removed, 

the remaining power spectral density has been modeled by Pearsons system of probability 

distributions. The coefficients of the probability distributions have been calculated by using two 

methods: method of moments and maximum likelihood estimation method. We have shown that 

the probability distributions of the power spectral density of the Langmuir waves belong to the three 

main types of Pearsons probability distributions: type I, type IV and type VI. This is in contradiction 

with the Stochastic Growth Theory (SGT) which predicts log-normal distribution for the power spectral 

density of the Langmuir waves. This result indicates that the SGT possibly requires additional 

verifications and examinations. 

We have modelled electrostatic Langmuir waves by an electric field, E(t), consisting of superposition 

of Gaussian wave packets with several probability distributions of amplitudes, log(A 2 ), and 

with several Poisson distributions of number of wave packets in 1 s. The outcome of the model and 

the simulations is that the plane of WIND observations, specially for low frequency receivers within 

WAVES experiment, can be covered by a combination of following assumptions: (1) from WIND 

observations is not possible to conclude whether the input wave amplitudes distributions are closer 

to log-normal than to Pearsons type I, or uniform; (2) the average number of wave packets in 1 s is 

between 0.1 and 50. Therefore, there is a clear need to measure Langmuir waves energy distributions 

directly at the waveform level and not a posteriori in the spectral domain.


Session 7 

Solar Instabilities, Flares, and Coronal Mass Ejections 

P.7.1. Multi-Spacecraft Reconstruction of the Magnetic 

Fields Inside Writhed ICMEs 

N.A. Al-Haddad 1,2 , I.I. Roussev 2 , C. Jacobs 1 , C. Möstl 3 , N. Lugaz 2 , 

S. Poedts 1 and C. Farrugia 4 

1 Centruum voor Plasam Astrofysica – Katholieke Universiteit Leuven, Leuven, Belgium 

2 Institute for Astronomy – University of Hawaii, Honolulu, USA 

3 Graz University & Austrian Academy of Sciences , Graz, Austria 

4 Space Science Center – University of New Hampshire, Durham, USA 


The properties of magnetic clouds (MCs) are primarily known from in situ measurements at 1 AU. 

Under certain assumptions (2.5-D, temporal invariance, force-free, etc...), the magnetic fields inside 

MCs can be reconstructed from these satellite measurements, usually resulting in the classical picture 

of twisted flux ropes. In a previous work, we have shown how reconstructing the magnetic field of 

synthetic in situ measurements from coronal mass ejections (CMEs) with writhed field lines structure, 

can yield a structure of a twisted flux rope. Here, we investigate the cases of multi-spacecraft measurements. 

We study different cases of two and three spacecraft with different orientation with respect 

to the CME axis. We analyse how the different separation and orientation can help us distinguish 

between writhed and twisted magnetic field. 

P.7.2. Multi-wavelength Observations of a Metric Type-II Event 

C.E. Alissandrakis 1 , A. Nindos 1 , S. Patsourakos 1 , A. Hillaris 2 and the 

ARTEMIS group 

1 Section of Astrogeophysics, Department of Physics, University of Ioannina, Ioannina GR-45110, Greece 

2 Section of Astronomy, Astrophysics and Mechanics, Department of Physics, University of Athens, 

Athens GR-15783, Greece 


We have studied a complex metric radio event, observed with the ARTEMIS radiospectrograph 

on February 12, 2010. The event was associated with a surge observed at 195 and 304 A and with 

a coronal mass ejection observed by STEREO A and B instruments near the East and West limbs 

respectively. On the disk the event was observed at 10 frequencies by the Nançay Radioheliograph 

(NRH), in H-alpha by the Catania observatory and in soft x-rays by GOES SXI. We combined these 

data, together with MDI longitudinal magnetic field, to get as complete a picture of the event as 

possible. Our emphasis is on two type-II bursts that occurred near respective maxima in the GOES 

light curves. The first, associated with the main peak of the event, showed a clear fundamentalharmonic 

structure, while the emission of the second consisted of three well-separated bands. Using 

positional information for the type-IIs from the NRH we explore their possible association with the 

surge, the coronal front and the CME. We also studied fine structured and fundamental-harmonic 

structure in the metric dynamic spectrum.


P.7.3. CME propagation directions derived from mass 

calculations and triangulation techniques 

B.M. Bein 1 , M. Temmer 1 , A.M. Veronig 1 and A. Vourlidas 2 

1 IGAM/Institute of Physics, University of Graz, Universitätsplatz 5, 8010 Graz, Austria 

2 Code 7663, Naval Research Laboratory, Washington, DC 20375, USA 


The STEREO (Solar Terrestrial Relations Observatory) mission consists of two nearly identical 

spacecraft, which observe the Sun from different vantage points. We use this potential to combine 

coronagraphic observations (COR1 and COR2) up to 15 RSun of both spacecraft to determine the 

kinematics and ’true’ CME mass for a sample of well observed events. The CME propagation direction 

is determined from mass calculations assuming that both spacecraft observe the same amount of mass 

(see Colaninno and Vourlidas, 2009). The outcome is compared to results derived from triangulation 

techniques using projected CME distances observed from the different vantage points and to the 

derived directions applying forward modelling (cf. Thernisien, Howard, Vourlidas, 2006). 

P.7.4. Dynamic of polar plumes observed during 2006, 

2008, 2009 and 2010 total solar eclipses 

M. Belik 1 , K. Barczynski 2 , and E.Markova 1 

1 Observatory Upice, Czech Republic 

2 Jagiellonian University, Krakow, Poland 


Based on observations of polar plume dynamic in the white-light corona during the total solar 

eclipse in 2006, the images obtained during multi-station observation of the 2008, 2009 and 2010 

eclipses were analyzed. Several polar plumes showing similar dynamic were identified. The speeds 

of these dynamic features were found by comparing pictures obtained in different times along the 

path of totality. Some of identified polar plumes were compared with the corresponding phenomena 

observed in X-plumes from the HINODE satellite. 

P.7.5. Cross-field transport of non-thermal electrons in 

thick-target coronal loops 

N.H. Bian 1 , E.P. Kontar 1 and A.L. MacKinnon 1 

1 School of Physics and Astronomy, Kelvin Building, University of Glasgow, GLASGOW G12 8QQ, UK 


Using RHESSI observations we previously found hard X-ray (HXR) source widths increasing with 

photon energy, allowing us to estimate the magnitude of the fast electron cross-field diffusion coefficient. 

To understand this we discuss the cross-field transport arising from broadband magnetic 

fluctuations in coronal loops, highlighting the importance of Kubo number K in distinguishing quasilinear 

and non-linear regimes of transport and tying together results applicable to large and small 

Kubo number regimes. The observed hard X-ray source widths allow us to place constraints on 

the level of magnetic fluctuations δB/B0 and on the parallel and perpendicular correlation lengths 

describing the turbulence. We deduce δB/B0 > 0.1, irrespective of the regime of transport, suggesting 

that turbulence plays a substantial role in flare energetics. A combination of arguments and 

observations also lets us constrain both correlation lengths to values within fairly narrow ranges.


P.7.6. Particle Acceleration at a Noisy X-Type Neutral Point 

C.A. Burge 1 , A.L. Mackinnon 2 and P. Petkaki 3 

1 Department of Physics & Astronomy, University of Glasgow, Glasgow, G12 8QQ 

2 DACE, University of Glasgow, Glasgow,G3 6NH 

3 Atomic Astrophysics, DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce 

Road,Cambridge, CB3 0WA 


We simulate the likely noisy situation near a reconnection region by superposing many X-type 

neutral point linear reconnection eigenmodes. By studying test particle orbits we show that more turbulent 

situations, simulated by superposing more and more eigenmodes, produce greater accelerated 

particle energies. We also describe the extension of test particle studies to include collisional energy 

loss and scattering, important for assessing the rate at which particles re-encounter the dissipation 

region. Possible application of these results to coronal hard X-ray sources is discussed. 

P.7.7. A model for the evolution of slow coronal mass 

ejections up to 1 AU 

S. Devriese 1 , C. Jacobs 1 , F. P. Zuccarello 1 , and S. Poedts 1 

1 Centrum voor Plasma-Astrofysica, K.U.Leuven, Celestijnenlaan 200B, 3001, Leuven, Belgium 


Coronal mass ejections (CMEs) are the most important drivers of the space weather and therefore 

many studies often focus on the fast and thus most dangerous events. However, the average CME 

propagates at a velocity close to the slow solar wind speed and especially during solar minimum fast 

CMEs are rather exceptional. But also the magnetic clouds driven by the slower events are recognised 

to be able to cause significant geomagnetic disturbances. 

In this research a CME was simulated under solar minimum conditions and its propagation was 

followed up to 1AU. The CME was initiated by shearing the magnetic foot points of a magnetic 

arcade which was positioned north of the equatorial plane and embedded in a larger helmet streamer. 

The overlying field deflects the CME towards the equator, where the deflection path is dependent on 

the driving velocity. The core of the CME consists out of a magnetic flux rope and the density shows 

the typical three part CME structure. The resulting CME propagates only slightly faster than the 

background solar wind, but the excess speed is high enough to create a fast shock from a distance 

of 0.3AU on. At 1AU the plasma shows the typical characteristics of a magnetic cloud, and the 

simulated data are in good agreement with the observations.


P.7.8. A Dynamic, Data-Driven Self-Organized Critical 

Model of Solar Active Regions 

M. Dimitropoulou 1 , H. Isliker 2 , M. K. Georgoulis 3 and L. Vlahos 2 

1 University of Athens, Department of Physics, GR-15483 Athens, Greece 

2 University of Thessaloniki, Department of Physics, GR-54006 Thessaloniki, Greece 

3 Research Center for Astronomy and Applied Mathematics, Academy of Athens, GR-11527 Athens, Greece 


We interpret solar flares as events originating in active regions having reached the self organized 

critical state, by using a sequence of observed magnetograms per active region as initial conditions and 

evolving them through a dynamic cellular automaton model. We show that all distinct initial magnetic 

snapshots in our sequence individually reach a self organized critical state. We statically (no time 

evolution considered) drive each of the magnetograms included in our sequence towards self organized 

criticality by applying a nonlinear force-free extrapolation that reconstructs the three-dimensional 

magnetic fields from two-dimensional vector magnetograms. We then locate magnetic discontinuities 

exceeding a threshold in the Laplacian of the magnetic field. These discontinuities are relaxed in local 

diffusion events, implemented in the form of cellular automaton evolution rules. Subsequent loading 

and relaxation steps lead the system to self organized criticality. Physical requirements, such as the 

divergence-free condition for the magnetic field vector, are approximately imposed on all elements 

of the model. The subsequent 3D magnetic fields are then connected in time direction through 

spline interpolation.This provides the dynamic evolution of our active region. Every interpolation 

step has a specific time stamp (magnetohydrodynamic scale) defined by the magnetograms’ attributes 

(temporal and spacial). The interpolation between two subsequent magnetograms makes the magnetic 

field evolve gradually and may lead to new magnetic discontinuities, which exceed a threshold in the 

magnetic field Laplacian . These discontinuities are then instantly relaxed (kinetic scale) in local 

diffusion events, by following the same cellular automaton evolution rules as in the static model 

described above. Our results show that self organized criticality is indeed reached when applying 

the specific loading and relaxation rules. Power-law indices obtained from the distribution functions 

of the modeled flaring events are in good agreement with observations. Single power laws (peak 

and total flare energy) are obtained, as are power laws with exponential cutoff and double power 

laws (flare duration). The results are also compared with observational X-ray data from the GOES 

satellite for our active-region sample. 

P.7.9. The X-ray continuum for the nonthermal distributions 

J. Dudík 1,2 , E. Dzifčáková 2 , J. Kaˇsparová 2 , M. Karlický 2 and ˇS. Mackovjak 1,2 

1 Dept. of Astronomy, Physics of the Earth and Meteorology, 

Faculty of Mathematics, Physics and Informatics, Comenius University, 

Mlynská dolina F2, 842 48 Bratislava, Slovakia 

2 Astronomical Institute of the Academy of Sciences of the Czech Republic, 

Fričova 298, 251 65 Ondˇrejov, Czech Republic 


The nonthermal κ- and n-distributions have been recently successfully diagnosed in the transition 

region and flare plasma. These diagnostics are based on the synthetic line spectra calculated by a 

modification of CHIANTI for nonthermal distributions. 

Here we present the calculations of isothermal free-free and free-bound continua for the nonthermal 

distributions, which complete the spectral synthesis for nonthermal distributions. One notable feature 

is the disappearance of ionization edges for n-distributions. These results offer a tool for sampling 

the low-energy part of distribution function in flare plasma, and also an independent method for 

diagnosing n-distributions. 

The effect of the nonthermal continua on the total radiative losses from the coronal and flare 

plasma is discussed.


P.7.10. Effect of the non-equilibrium ionization in the flares on 

the diagnosed plasma parameters from X-ray line spectra 

E. Dzifčáková 1 

1 Astronomical Institute of the Academy of Sciences of the Czech Republic, Fričova 298, 251 65 Ondˇrejov, Czech Republic 


The strong heating during the impulsive phase of the flares can result in the non-equilibrium 

ionization. Therefore, the non-equilibrium X-ray line spectra can be observed. We have calculated 

time-dependent non-equilibrium ionization and synthetic X-ray line spectra for the plasma parameters 

derived from RHESSI or RESIK flare spectra for different electron densities. The synthetic spectra 

are compared with the observations and the effect of the non-equilibrium ionization on the diagnosed 

plasma parameters is analyzed. 

P.7.11. Updated ionization equilibrium for the 

kappa-distributions 

E. Dzifčáková 1 and J. Dudík 2 

1 Astronomical Institute of the Academy of Sciences of the Czech Republic, Fričova 298 

251 65 Ondˇrejov, Czech Republic 

2 Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina F2 

842 48 Bratislava, Slovakia 


Recently, new atomic data for the calculation of the ionization and recombination rates together 

with updated ionization equilibrium for the Maxwellian distribution have been published. We have 

used these atomic data for the calculation of the updated ionization equilibrium for the non-thermal 

kappa-distributions with an enhanced number of electrons in the high-energy tail. We have included 

the photo-ionization process into our calculations of the ionization equilibrium, too. The results are 

compared with the previous calculations and consequences for the spectroscopic diagnostics in the 

solar corona are discussed. 

P.7.12. On the existence of two different mechanisms of 

coronal mass ejection formation 

V.G. Eselevich 1 , M.V. Eselevich 1 , V.A. Romanov 2 , D.V. Romanov 2 

and K.V. Romanov 2 

1 Institute of solar-terrestrial physics 

2 Krasnoyarsk state pedagogical university 


Data from Mark 3 and 4, PICS (Mauna Loa Solar Observatory), and from spacecraft STEREO 

(EUVI) were analyzed. It is demonstrated that the difference between the physical nature of the 

“impulsive” and the “gradual” CMEs is mainly represented by such parameters as the CME location, 

velocity and angular size at the moment the CME emerges. The “gradual” CMEs are formed in the


corona at 0.1R⊙ < h ≤ 0.7R⊙ above the limb of the Sun (R⊙ is the solar radius). They start moving, 

when their angular size is 15-65 degrees (in the heliocentric coordinate system) and their initial 

velocity V0 ≈ 0. A probable mechanism for their formation is the eruption of a coronal flux rope from 

the equilibrium state. The formation of “impulsive” CMEs appears to begin under the photosphere 

of the Sun and may be related to ejection of floating magnetic tubes (flux ropes) from the convective 

zone. At the photospheric level, the radial velocities of such magnetic tubes exceed the local sound 

velocity and may reach hundreds km/s, while their angular sizes do not exceed ≈ (1 − 5) ◦ . Possible 

ejection of magnetic tubes from the convective zone was theoretically demonstrated earlier. 

P.7.13. Kinetic Simulations of CME Foreshock Radio 

Emissions 

U. Ganse 1 , P. Kilian 1 , F. Spanier 1 and R. Vainio 2 

1 Lehrstuhl für Astronomie, Universität Würzburg 

2 Department of Physics, University of Helsinki 


Emission of type II radio bursts in conjunction with CME shock fronts has been observed for 

many years, yet a lot of details of the plasma processes involved are still unknown. 

The fact that the bursts’ radio emission is narrowband points to a very spatially confined emission 

region, rather then a broad emission area along the complete shock front. Recent models locate this 

region in the foreshock of the CME, where a strong electron beam population from shock drift 

acceleration interacts with the solar wind plasma, leading to beam-driven instabilities. 

The Langmuir waves formed in this process then cause a number of possible three-wave interaction 

processes, which terminate in the observed fundamental and harmonic emission of electromagnetic 

waves. 

While in-situ observations of these processes are scarce, a number of satellite fly-thoughs have 

confirmed the validity of the scenario - but for detailled information about the wave physics, 3D data 

as obtainable from kinetic simulations are required. 

Using our fully relativistic, 2D and 3D particle-in-cell code ACRONYM, we are studying kinetic 

plasma wave interactions in beamed electron plasmas and attempting to confirm the theoretical 

predictions of type II radio burst emission processes. 

P.7.14. A multi-spectral radio burst observed up to 200 GHz 

C.G. Giménez de Castro 1 , G.D. Cristiani 2 , P.J.A. Simões 1 , 

C.H. Mandrini 2 and P. Kaufmann 1,3 

1 Centro de Rádio Astronomia e Astrofísica Mackenzie, Universidade Presbiteriana Mackenzie, São Paulo, Brazil. 

2 Instituto de Astronomía y Física del Espacio, Buenos Aires, Argentina. 

3 Centro de Componentes Semicondutores, Universidade Estadual de Campinas, Campinas, Brazil 


Flare emission > 1 GHz is considered of gyrosynchrotron origin, and its optically thin radiation 

can be approximated by a power law dependence on frequency. This simple picture is sometimes 

broken by flares which show complex spectra. We present in this work a combined wavelength 

analysis of the event occurred on September 10, 2002, at 14:53 UT on NOAA AR 10105, classified as 

GOES M3.2. We use radio data from 1 to 212 GHz and RHESSI images and spectra ≤ 200 keV. This 

is the weakest soft X-ray event whose radio burst counterpart is observed at sub-THz frequencies. 

The radio spectrum presents a low and a high components, with peaks at around 10 and 40 GHz 

respectively. Moreover, the 212 GHz emission onset has a 20 s delay respect to the 8.8 GHz onset. On 

the other hand, the HXR light curve returns to pre-flare levels 1 minute before radio emission does


the same. Assuming that the electrons producing the bremsstrahlung have a power law distribution 

in energy, from the HXR spectra we have determined the electron index and the total number of 

accelerated electrons at different time intervals. Both parameters are in agreement with similar 

results obtained from the low frequency radio spectrum, although the electron index varies in time in 

an opposite way. Furthermore, we could determine the time evolution of the electron injection, finding 

at least two different injection episodes. Besides, the high frequency radio spectrum is produced by 

a harder electron distribution in a more confined area. We analyse the observations in terms of a 

trap+precipitation model, and discuss the transport effects over the accelerated electron distribution. 

P.7.15. Microwave emission of the Active Region NOAA 

11158 before and after the flare X 2.2 on February 15, 2011 

I.Yu. Grigoryeva 1 and V.N. Borovik 1 

1 Central (Pulkovo) Astronomical Observatory of RAS, Saint-Petersburg, Russia 


Evolution of microwave emission of the AR NOAA 11158 during 13-16 February 2011 is considered. 

We concentrate on the microwave emission of the AR during some days before the X 2.2 flare occurred 

on February 15, 2011. Daily solar multi-wavelengths observations in the range of 1.65 – 5.0 cm with 

the RATAN-600 radio telescope have been used. The most intensive radio emission associated with 

the magnetic polarity inversion line in the AR began to be detectable two days before X 2.2 flare. 

Considerable microwave features were observed on February 14, 2011. The characteristics of the local 

radio sources associated with the Active Region NOAA 11158 are analyzed and discussed. 

P.7.16. Study of a C4.3 solar flare from AR NOAA 11123 

observed simultaneously with IBIS/DST, ROSA/DST, 

SDO/AIA and RHESSI 

Z. Huang 1 , M. Madjarska 1 , J.G. Doyle 1 , K. Reardon 2,3 , M. Mathioudakis 4 , 

G. Dorrian 4 , E. M. Scullion 5 , R. Milligan 6 


2 INAF - Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy 

3 NSO/Sacramento Peak, PO Box 62, Sunspot, NM 88349-0062, USA 

4 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University, Belfast BT7 1NN, N. Ireland 

5 Institute of Theoretical Astrophysics, University of Oslo, Blindern, N-0315 Oslo, Norway 

6 Laboratory for Solar Physics, Code 671, Heliophysics Science Division, NASA Goddard Space Flight Center, 

Greenbelt, MD 20771, USA 


We observed a GOES C4.3 solar flare that occurred between 15:54 UT to 16:27 UT on 2010 

November 11 in active region NOAA 11123. The flare was observed simultaneously from the ground 

and space. The ground-based observations were taken with the Interferometer BIdimensional Spectrometer 

(IBIS) and Rapid Oscillations in the Solar Atmosphere (ROSA) at NSO. With IBIS, we are 

able to study the flare in white light, blue and red wings of Hα 6563 ˚A plus minus 0.8 ˚A together with 

15-pt line profile scans, at 17 seconds cadence. With ROSA, we obtained multi-wavebands including 

the G-band, the Balmer continuum at 4170 ˚A, the Ca II K line, the blue continuum at 3510 ˚A plus 

Fe I 6302 ˚A magnetograms. The cadence ranged from sub-second for the G-band to 5 seconds for 

Ca II K. Together with observations from SDO/AIA and RHESSI, we aim to study how the flare 

evolved, how the energy was released, propagated and transferred throughout the solar atmosphere.


P.7.17. Multi-thermal observations of the Boss’s Day flare: 

a vertical kink mode, a CME, and post-flare loops 

A. R. Inglis 1 , S. Christe 1 



On 2010 October 16th SDO/AIA observed its first flare using automatic exposure control, the 

Boss’s Day flare. Coincidentally, this flare also exhibited a number of interesting features. Firstly, a 

faint CME emanates from the flare kernel, visible in AIA and observed traveling to the solar west at 

an estimated speed of ≈ 700-900 km/s. Later velocity estimates with LASCO/C2 however indicate a 

much lower velocity of ≈ 300 km/s, indicating significant deceleration. Secondly, a large flare ribbon 

significantly to the west of the flare kernel was ignited and was visible in all AIA wavelengths, posing 

the question as to how this energy was deposited and how it relates to the main flare site. Thirdly, a 

vertically polarised kink mode was excited far from the flare kernel and was the subject of a recent 

coronal seismological study by Aschwanden & Schrijver (2011). 

The causality of this event is unclear. One possibility is that this CME is responsible for both the 

heating of the ribbon and the kink mode excitation. However, closer scrutiny reveals that the flare 

site and the ribbon are connected magnetically via coronal loops which are heated during the main 

energy release. We investigate whether the ribbon heating and kink oscillation are triggered by the 

CME, the connecting loops, or a combination of these two effects. 

We also investigate whether the post-flare loops are subject to straightforward cooling, or whether 

re-heating effects occur. Using the multi-temperature capabilities of AIA in combination with 

RHESSI, and by employing cross-correlation mapping and the newly-available temperature mapping 

method developed by Aschwanden, we measure the loop temperatures as a function of time over 

several post-flare hours and hence measure the loop cooling rate. We find that the cooling time from 

10 MK to approximately 1 MK is ≈ 70 minutes. 

P.7.18. Spatially resolved polarisation across hard X-ray 

(HXR) sources from solar flares 

N. L. S. Jeffrey 1 , M. Battaglia 1 and E. P. Kontar 1 

1 School of Physics & Astronomy, University of Glasgow, G12 8QQ 


In the Sun’s atmosphere, flare events produce high energy electrons ( tens of keV) that propagate 

into the chromosphere producing Hard X-ray (HXR) photons via bremsstrahlung. HXR photons 

emitted away from the Sun will propagate freely into interplanetary space while HXR emitted towards 

the photosphere are either absorbed or Compton scattered. Compton scattering leads to a ‘reflected’ 

albedo component that is always observed in conjunction with the primarily produced bremsstrahlung 

component, and hence leads to an alteration in the observed HXR emission, greatest at peak scattering 

energies of 20-50 keV. Amongst many other important consequences of such reflection, the albedo 

component alters the polarisation of the primary HXR source, a property that is highly dependent 

on the directivity of the HXR distribution and hence the parent electron distribution produced by 

the flare. 

Monte Carlo simulations of photon transport in the photosphere have been used in order to 

simulate radiation transfer of polarized X-ray photons and to infer the Stokes parameters. We present 

the first results of spatially resolved polarisation for a single HXR source due to the presence of an


albedo component and discuss the potential of future spatially resolved polarization measurements 

to help constrain the electron directivity for an individual flare and to optimize the future X-ray 

imaging polarimetry missions. 

P.7.19. Pre-flare activity and role of magnetic reconnection 

during the evolutionary phases of a solar eruptive flare 

Bhuwan Joshi 1 , Astrid Veronig 2 , S.-C. Bong 3 , S. K. Tiwari 4 , J. Lee 5 , 

K.-S. Cho 3 

1 Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313 001, India 

2 IGAM/Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz, Austria 

3 Korea Astronomy and Space Science Institute, Daejeon 305-348, Korea 

4 Max Planck Institute for Solar System Research, Max Planck Str 2, 37191, Katlenburg-Lindau, Germany 

5 Physics Department, New Jersey Institute of Technology, 161 Warren Street, Newark, NJ 07102 


In this paper, we present a multi-wavelength analysis of an eruptive white-light flare of GOES class 

M3.2 which occurred in the active region NOAA 10486 on November 1, 2003. The availability of the 

excellent set of high resolution observations from three space missions, RHESSI, TRACE, and SOHO, 

have enabled us to study the magnetic coupling of different layers of the solar atmosphere during 

various evolutionary phases of the eruptive flare. The flare exhibits a significant pre-flare processes for 

∼9 minutes before the onset of the impulsive phase. The initial pre-flare activities are inferred from 

TRACE images at EUV/UV wavelengths as the brightenings in the highly sheared core region close 

to the filament and changes in the configuration of short, low-lying loops. This initiation phase is 

followed by the X-ray precursor phase, which is manifested in RHESSI measurements below ∼30 keV. 

During this phase, the X-ray emission is dominantly thermal with the plasma temperature ∼27 MK 

already at the very start. The very first signature of eruption was observed at this time as the bright 

arc-like structure. The pre-flare evolution suggests an “internal slow reconnection” and is consistent 

with the tether-cutting process associated with the flux emergence. Plasma temperature attains a 

maximum (∼30 MK) in the early impulsive phase during which EUV flaring region undergoes large 

structural changes. The impulsive phase is characterized by two HXR bursts at a separation of ∼3 

minutes with X-ray emission originating from two footpoint sources and a looptop source. During 

this phase, the flare spectrum is composed of a thermal component of temperature ∼22–30 MK, and 

a non-thermal component with photon spectral index γ = 3.6–6.0. The present study indicates a 

causal relation between the activities in the preflare and main flare. The study further suggests that 

the reconnection during the pre-eruption phase could be very different from the post-eruption coronal 

reconnection which is generally viewed in terms of the standard flare model. 

P.7.20. Radio pulsating structures associated with coronal 

loop contraction 

J. Kallunki 1,2 , S. Pohjolainen 2 

1 Aalto University, Metsähovi Radio Observatory, Kylmälä, Finland 

2 Department of Physics and Astronomy, Tuorla Observatory, University of Turku, Piikkiö, Finland 


A CME-related, GOES M8.6 class flare occurred in an active region located at N10 E35 on 20 

July 2004. During the flare, the overlying coronal loops showed downward movement in the SOHO 

EIT images, which was interpreted as possible coronal implosion in an earlier study. We investigate


this event further using TRACE, GOES SXI, and Nancay Radioheliograph imaging, together with 

wide-range radio dynamic spectral data and flux density observations at microwaves. 

At the time when the flare impulsive phase started, drifting pulsating structures appeared in 

the radio dynamic spectra near 1.6 GHz at 12:26 UT. Simultaneous periodic oscillations were also 

detected in the microwave flux. Our periodicity analysis (Wavelet, Global Wavelet Spectrum and Fast 

Fourier Transform) revealed various quasi-periodic pulsating structures at periods of 3 – 15 seconds, 

both at decimetric-metric and microwave range. The radio dynamic spectra were investigated at 

various frequencies between 100 MHz – 4 GHz (Phoenix, ETHZ), and microwave flux at 8, 11, 19 

and 35 GHz (Bumishus). The SXI imaging with two-minute time resolution showed the time of loop 

contraction, associated with radio pulsations imaged at metric wavelengths (Nancay). 

We discuss the possible origin of the decimetric-metric pulsations and their relation to the contracting 

coronal loops. The later loop expansion leading to a halo coronal mass ejection is also 

described and considered. 

P.7.21. A quantitative interpretation of multi-wave emission 

from the impulsive pre-flare event of 16 August 2004 

L.K. Kashapova 1 , V.V.Zharkova 2 , V.V. Grechnev 1 , G.V. Rudenko 1 , A.A. 

Kuznetsov 3 and T.V. Siversky 2 

1 Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences, P.O. Box 291, 

Irkutsk 33, 664033, Russia 

2 Department of Mathematics, SCIM, University of Bradford, BD7 1DP, UK 

3 Armagh Observatory, Armagh BT61 9DG, Northern Ireland 


We present the quantitative interpretation of hard X-ray (HXR), microwave (MW) and Hα observation 

of the event occurred before the 16 August 2004 flare. The considered event was a very 

impulsive one (duration less then 15 seconds) with the pronounced MW and HXR emission indicating 

a presence of accelerated electrons with the energies up to 100 keV. Moreover, the event comprises the 

two separate sources having a close temporal correlation in HXR, MW and Hα emissions. The flare 

eastern source was connected both with HXR and MW emission sources but the western flare source 

demonstrated only the MW and chromospheric emission. The interpretation is based on simultaneous 

simulation of HXR and MW emission with the same populations of electrons using Fokker Planck 

(FP) kinetic model of precipitation of electron beam in a converging magnetic field. We restored 

a magnetic field configuration for this event and carried out simultaneous simulations of HXR and 

MW emission for several moments of the event, in order to derive electron beam properties at various 

precipitation depths. The numerical model was appended by Hα emission simulation in different 

kernels. The possible scenarios of this event dynamics are discussed including the effects of high 

energy electrons and low-energy protons and possible role in triggering the main flare event. 

P.7.22. Detection of acceleration processes during the 

precursor of the 12 June 2010 flare 

M.S. Kisil 1 , L.K. Kashapova 1 and N.S. Meshalkina 1 

1 Institute of Solar-Terrestrial Physics, Siberian Branch of the Russian Academy of Sciences, P.O. Box 291, 

Irkutsk 33, 664033, Russia 


We present analysis of plasma parameters during the negative precursor of the 12 June 2010 

flare (SOL2010-06-12T00:57). A comparison of results obtained from microwave(MW) data by the


Nobeyama Radio polarimeter and the Siberian Solar Radio Telescope (the 10-antenna radio heliograph 

prototype at 4.6 and 6.4 GHz) and hard X-ray (HXR) observations by RHESSI and Fermi was 

carried out. MW spectra indicate to gyrosynchrotron mechanism of microwave emission excitation 

and presence of accelerated electrons. The study revealed that fluxes at several HXR energy bands 

and MW frequencies demonstrated a good temporal correlation during the precursor. It specified 

that the detected HXR and MW emission was generated by the same populations of accelerated 

electrons. An interpretation implying existence of particle acceleration during precursor is discussed 

taking into account the plasma parameters obtained both from HXR and MW emissions. 

P.7.23. A simulation study of overexpanding CME cavities 

B. Kliem 1,2 , T. G. Forbes 3 , A. Vourlidas 4 , and S. Patsourakos 5 



3 EOS Institute, University of New Hampshire, Durham, NH, USA 

4 Space Science Division, Naval Research Laboratory, Washington, DC, USA 

5 Department of Physics, University of Ioannina, Ioannina, Greece 


Coronal mass ejection (CME) cavities seen in white-light coronagraphs expand nearly self similarly 

in the outer corona and inner solar wind. Little is known about their initial expansion in the inner 

corona. The expansion of the cavity in a fast CME was recently quantified in this range by Patsourakos 

et al. (2010), using stereoscopic SECCHI data. A very rapid initial expansion with indications for an 

“overexpansion”, characterized by increasing ratio of cavity radius by height, was found in the low 

corona. This was followed by approximately self-similar expansion. We present MHD simulations of 

flux rope CMEs which address the formation and initial expansion of a cavity. The expansion is found 

to consist of two components. The first of these is due to an ideal MHD effect. The information of 

decreasing flux rope current in the course of the rope’s ascent propagates into the medium surrounding 

the flux rope and causes it to expand all around the rope by virtue of flux conservation. The second is 

due to the addition of flux to the rope by flare reconnection. The ideal MHD effect dominates initially 

if the ambient field is only weakly sheared, producing a cavity outside of the growing flux rope. This 

rapidly growing “outer cavity” is a prime candidate for the formation of coronal EUV waves and 

shocks. Subsequently, the growth of the rope due to flare reconnection leads to an approach of the 

rope and outer-cavity edges. We conclude that the CME cavity may be larger than the CME flux 

rope low in the corona if the ambient field is only weakly sheared and that cavity and rope tend to 

coincide in the outer corona and solar wind. 

P.7.24. Bald-patch versus X-type sigmoids: Implications for 

the magnetic topology at the onset of solar eruptions 

B. Kliem 1,2 and L. M. Green 2 




Sigmoidal soft X-ray and EUV sources are formed by dissipation in current-carrying coronal 

magnetic fields. Thus, they may reveal the topology of the field prior to and in the course of eruptions. 

Recent research has led to improved understanding whether a sigmoid outlines field lines of arcade or 

of flux rope structure, but the specific topology in case of an underlying flux rope remains debated. 

A pure O-type topology with a “bald-patch separatrix surface (BPS)” in the interface to the ambient 

flux competes with a mixed topology, which includes an X-type structure referred to as “hyperbolic


flux tube (HFT)” between the flux rope and the photospheric boundary. We analyse a small sample 

of eruptive sigmoidal sources, including their development toward the eruption over several days. All 

events occurred in decaying active regions which showed ongoing flux cancellation. Properties like the 

inverse crossing of the photospheric polarity inversion line by the sigmoid centre and the stationarity 

and (at least partial) survival of the sigmoid through the eruption demonstrate that most sigmoids 

in the sample belong to the BPS category. However, one case is clearly of HFT structure. Possible 

reasons for the dominance of BPS sigmoids in the sample will be discussed. 

P.7.25. A parametric study of CME rotation in the corona 

B. Kliem 1,2 , T. Török 3 , and W. T. Thompson 4 



3 Predictive Science, Inc., San Diego, CA, USA 

4 NASA Goddard Space Flight Center, Greenbelt, MD, USA 


Many erupting filaments and coronal mass ejections rotate about the direction of ascent. Substantial 

rotation angles are often indicated already within the low corona. It is of interest to understand 

the physical processes which control this rotation, since the orientation of CMEs is one of the two 

major parameters that determine the geoeffectiveness of ejections directed at the Earth (the other is 

the CME speed). Two mechanisms have been proposed to explain the rotation at coronal heights: 

the helical kink instability and the Lorentz force by a shear field component due to sources external 

to the erupting flux. We present a parametric study of these effects in force-free equilibria containing 

a flux rope, confirming the relevance of both mechanisms. Three parameters of strong influence on 

the resulting total rotation are identified: twist, external shear field strength, and height profile of the 

external field. The individual contributions of the two mechanisms to the total rotation are difficult 

to disentangle. However, the height profile of the rotation, which can now be obtained for some events 

from stereoscopic observations, allows to constrain the individual contributions to some degree. This 

will be illustrated using the first such profile, derived from STEREO data of the “Cartwheel CME” 

on 9 April 2008. 

P.7.26. Kinematics and Helicity Evolution of a Loop-Like 

Eruptive Prominence observed on 30 March 2010 with AIA on 

SDO 

K. Koleva 1 , P. Duchlev 1 , M.S. Madjarska 2 , J.-C. Vial 3 , C.J. Schrijver 4 , 

M. Dechev 1 and E. Buchlin 3 

1 Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, 

72 Tsarigradsko Shose Blvd., 1784 Sofia, Bulgaria 


3 Institut d’Astrophysique Spatiale, Université Paris-Sud and CNRS, 91405 Orsay, France 

4 Solar and Astrophysics Lab., Lockheed Martin Advanced Techn. Ctr., 3251 Hanover St., Bldg. 252, 

Palo Alto, CA 94304-1191, USA 


In this work, we examine the kinematic, morphological, and helicoidal pattern of a loop-like 

eruptive prominence (EP) observed on 30 March 2010 in the EUV He ii 30.4 nm and Fe ix 17.1 

nm lines by the AIA instrument of the Solar Dynamics Observatory. The study is performed in the 

context of the magnetic flux rope (MFR) hypothesis of solar prominences. The evolution of the EP 

MFR and the signatures of the kinking of the MFR axis are used to test the role of the kink instability 

in the prominence eruption.


P.7.27. Dynamics of the new-cycle active region NOAA 11024 

N.N. Kondrashova 1 , M.N. Pasechnik 1 , S. N. Chornogor 1 

and E. Khomenko 2,3 

1 Main Astronomical Observatory, NASU, Ukraine 

2 Instituto de Astrofísica de Canarias, 38205 La Laguna, Spain 

3 Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Spain 


We present the results of the dynamics study of the active region NOAA 11024 at the new solar 

activity cycle onset phase using data of space and ground-based observations. A combination of 

GOES, SOHO, STEREO data and the observations on July 4, 2009 with the French-Italian THEMIS 

telescope (Obsevatorio del Teide of the Instituto de Astrofisica de Canarias) allowed us to investigate 

the dynamics of active region atmosphere in a wide range - from the photosphere to the corona. 

To study the line-of-sight velocity field at the lower atmospheric levels we have used one of the 

time series of high resolution spectra, obtained in the chromospheric Hα line and four Fraunhofer 

lines formed at different levels in the photosphere (FeI 6301.5, 6302.5, 6303.5 ˚A and TiI 6303.7 ˚A). 

The spectrograph slit crossed two sunspots (large and small), two plages (quiet and active), and the 

ejections. We have analyzed velocity and intensity temporal variations, obtained at different heights 

of the photosphere and the chromosphere. Strong changes of the chromospheric velocity and intensity 

with time and along the solar surface are revealed. The Hα and EUV-images showed the moving 

heated plasma along the loop from one base to another. The evolution of the active region was 

accompanied by the downward chromospheric motions. The ascending velocities during the ejection 

attained more than 60 km/s. Upward mass motions were observed in all the photospheric layers 

during the observations. The temporal changes of the chromospheric and photospheric velocities 

were most drastic in the active plage and small spot regions. 

The velocity field pattern and space observations data favors the magnetic reconnection models, 

especially those in which weak reconnections of small-scale magnetic structures occur at the lower 

atmospheric level. 

P.7.28. Hard X-ray observations of magnetic turbulence, 

acceleration and electron transport in a dense flaring loop 

E.P. Kontar 1 , I.G. Hannah 1 , and N.H. Bian 1 

1 School of Physics and Astronomy, University of Glasgow, G12 8QQ, UK 


Magnetic turbulence is an important but poorly understood element of many processes involved 

in solar flares, including magnetic reconnection, particle acceleration, and transport. Using Ramaty 

High Energy Solar Spectroscopic Imager (RHESSI) observations and the X-ray visibility analysis, we 

determine the spatial and spectral distributions of energetic electrons in and near the acceleration 

site. Energy-dependent transport of tens of keV electrons is observed to occur both along and across 

the guiding magnetic field of the loop. We show that the cross-field transport is consistent with 

the presence of magnetic turbulence in the loop, where electrons are accelerated, and estimate the 

magnitude of the field line diffusion coefficient for different phases of the flare. The level of magnetic 

fluctuations peaks when the largest number of electrons is accelerated in the flare and is below 

detectability or absent at the decay phase. The energy density of the magnetic fluctuations is found 

to be comparable with the energy density of non-thermal particles. These hard X-ray observations 

provide the first observational evidence that magnetic turbulence governs the evolution of energetic 

electrons in a dense flaring loop and is suggestive of their turbulent acceleration.


P.7.29. Modelling of Hα eruptive events observed at 

the solar limb 

P. Kotrč 1 , M. Bárta 1 , P. Schwartz 1,2 and Yu. A. Kupryakov 3 

1 Astronomical Institute, Academy of Sciences of the Czech Republic, Ondˇrejov, Czech Republic 

2 Astronomical Institute, Slovak Academy of Sciences, Tatranská Lomnica, Slovakia 

3 Sternberg Astronomical Institute, Moscow, Russia 


Spectra and slit-jaw images of limb flares and eruptive prominences were observed with a high 

temporal resolution by the Ondrejov observatory optical spectrograph. Both emission and absorption 

patterns found in the spectra and filtergrams are used to restore and describe dynamic processes 

occurring in early and late phases of eruptive events. Kinematic and MHD models are used for 

simulations of the processes and the observed spectral patterns. Estimation of parameters associated 

with plasma flows and expulsion is carried out. 

P.7.30. Radio Emission Associated with Solar Energetic 

Particle Events 

A. Kouloumvakos 1,2 , A. Nindos 2 ,P. Preka-Papadema 1 , A. Hilaris 1 , 

C. Caroubalos 3 , X. Moussas 1 , C. Alissandrakis 2 P. Tsitsipis 4 

and A. Kontogeorgos 4 


2 Department of Physics, University of Ioannina, Greece. 

3 Department of Informatics, University of Athens. 

4 Department of Electronics, Technological Education Institute of Lamia, Lamia, Greece. 


The corona probed at meter and decimeter wavelengths is a crucial region for the acceleration and 

propagation of solar energetic particles (SEPs), and radio diagnostics in this plasma plays a major role 

in assessing the origin of SEP events. Using data from the ARTEMIS IV solar radio spectrograph, we 

report the properties of the radio emission associated with several major SEP events. The association 

of the radio emission with the related flares and CMEs is also investigated. The results reported in 

this presentation were obtained in the framework of the SEPServer project, funded from the European 

Commission’s Seventh Framework Programme.


P.7.31. Type II Radio Emission from Shock Formation In The 

Low Corona on 13-Jun-2010: Combined Observations from the 

ARTEMIS-IV Radiospectrograph and SDO/AIA 

A. Kouloumvakos 1 , A. Vourlidas 2 ,P. Preka-Papadema 1 , A. Hilaris 1 , 

C. Caroubalos 3 , X. Moussas 1 , P. Tsitsipis 4 and A. Kontogeorgos 4 


2 Naval Research Laboratory. 

3 Department of Informatics, University of Athens. 

4 Department of Electronics, Technological Education Institute of Lamia, Lamia, Greece. 


High cadence observations in the low corona from AIA imagers combined with radiospectrograph 

high-resolution recordings give a new perspective of shock formation in the low corona. Using 

ARTEMIS-IV observations of drifting type-II metric radio emission and ultra-high resolution observations 

from the AIA imagers we present direct observation of shock formation in the EUV and its 

association to the accompanying type-II during the 13-Jun-2010 Event. We will show that, in this 

case, the coronal expansion driven by the formation of the CME ejecta is responsible for both EUV 

and radio emissions. 

P.7.32. X-class SXR flares of solar cycle 23 with and without 

SOHO/LASCO coronal mass ejections and type II shocks 

E. Lavassa 1 , P. Preka-Papadema 1 , A. Hillaris 1 , A. Kouloumvakos 1 , X. 

Moussas 1 



The relationship of CME characteristics and the associated flare properties may contribute to the 

understanding of the common magnetic instability at the origin of the combined active phenomenon. 

Although the CME-flare association is very high for X type flares, there are still few of them which 

appear CME-less. There are also some CME-Flare events which are not accompanied by metric type II 

shocks. This poses the question whether these two categories of flares exhibit different characteristics 

from the usual CME and type II associated majority of X flares. This work presents a study of the 

characteristic properties of X-class SXR flares in the 23rd solar cycle. Events are categorized, into 

CME associated, CME and Type II associated and CME-less with their properties compared and 

contrasted by category, in order to find similarities and differentiations among categories.


P.7.33. Numerical Investigation of a CME from an Anemone 

Active Region: Reconnection and Deflection 

N. Lugaz 1 , C. Downs 1 , I. I. Roussev 1 , K. Shibata 2 , A. Asai 2 and 

T. I. Gombosi 3 

1 Institute for Astronomy, Univ. of Hawaii, 2680 Woodlawn Dr., Honolulu, HI, 96822 USA 

2 Kwasan Observatory, Kyoto University, Japan 

3 CSEM, Univ. of Michigan, USA 


We present a numerical investigation of the coronal evolution of the coronal mass ejection (CME) 

on 2005 August 22 using a 3-D thermodynamics MHD model, the SWMF. The source region of the 

eruption was anemone AR 10798, which emerged inside a coronal hole. We validate our modeled 

corona by producing synthetic EUV images, which we compare to EIT images. The CME is initiated 

with an out-of-equilibrium flux rope with an orientation chosen in agreement with observations of an 

Hα filament. During the eruption, one footpoint of the flux rope reconnects with streamer magnetic 

field lines and with open field lines from the adjacent coronal hole. It yields an eruption which has 

a mix of closed and open twisted field lines due to interchange reconnection and only one footpoint 

line-tied to the source region. We identify a dimming region associated with the reconnection process. 

We discuss the implication of our results for the arrival at Earth of CMEs originating from the limb 

and for models to explain the presence of open field lines in magnetic clouds. 

P.7.34. Diagnostic of the κ-distributions from Al, Ca, O, 

and S lines in HINODE/EIS spectra 

ˇS. Mackovjak 1,2 , E. Dzifčáková 2 and J. Dudík 1,2 

1 Department of Astronomy, Physics of the Earth and Meteorology, Faculty of Mathematics, 

Physics and Informatics, Comenius University, Mlynská dolina, 842 48 Bratislava, Slovakia 

2 Astronomical Institute Academy of Science of the Czech Republic, 251 65 Ondˇrejov, Czech Republic 


The non-thermal κ-distributions are widely used e.g. for the description of the electron distribution 

function in the solar wind. Recently it has been shown that the relative intensities of the Si III lines 

in transition region can be explained by κ-distributions, too. We have investigated the possibilities to 

diagnose this type of non-thermal distribution in the active region and flare spectra observed by the 

EUV Imaging Spectrometer (EIS) on board the HINODE spacecraft in its two spectral bands (163- 

212 ˚A and 242-292 ˚A). We have calculated the synthetic spectra for the different κ-distributions and 

searched for all EUV line ratios sensitive to the shape of the distribution function. Only a relatively 

small number of the line ratios belonging to elements Al, Ca, O and S are sensitive to the type of 

distribution. Preliminary comparison with the ratios of the line intensities from the EIS spectral atlas 

is shown, with clear signatures of plasma non-thermality.


P.7.35. The role of the slow mode shocks in the reconnection 

region for generating energetic electrons during solar flares - 

RHESSI results 

G. Mann 1 , H. Aurass 1 , H. Önel 1 , and A. Warmuth 1 

1 Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany 


During solar flares the Sun emits an enhanced intensity of electromagnetic radiation from the 

radio up to the gamma-ray range indicating the generation of energetic electrons. In the standard 

flare model in terms of magnetic reconnection, pairs of slow mode shocks occur and separate the infrom 

the outflow region. The aim of this talk is to study which role these slow mode shocks play 

for the generation of energetic electrons. At these slow mode shocks, magnetic energy is efficiently 

transferred into kinetic energy leading to the generation of energetic electrons in the outflow region. 

The spectra of these electrons are theoretically calculated and compared with those observed by 

RHESSI during 9 X-class flares. That allows to deduce parameters, e.g. electron number density, 

magnetic field and temperature, in the flare region. For instance, flares take place in region with a 

typical Aflvén-velocity in the range 3000-4000 km/s. 

P.7.36. Directivity and spatial variations of hard X-rays in 

solar flares 

V.F. Melnikov 1,2 , Yu.E. Charikov 3 and I.V. Kudryavtsev 3 

1 Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, 196140, Saint-Petersburg, Russia 


3 Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021, Saint-Petersburg, Russia 


A goal of the study is to obtain constraints on the type of pitch-angle distribution of electrons 

accelerated in solar flares. For this, a modeling of temporal and spatial distributions of hard Xray/gamma-ray 

emission has been conducted. We considered two models with the relativistic (30 keV 

- 10 MeV) electrons injection localized in the loop top. One model is with an electron beam highly 

directed along a magnetic loop, and another one with isotropic pitch-angle distribution. We have 

solved the time-dependent Fokker-Planck equation for relativistic electrons in a converging magnetic 

field. Directivity, spatial distributions of the intensity, energy spectrum, and polarization degree of 

hard X-ray/gamma-ray emission were analyzed. It is shown that the bright hard X-ray source in the 

loop top is formed in the case of the isotropic injection. A high directivity is a characteristic feature 

of its emission. The ratio of the transverse intensity to longitudinal one is 2 to 10 in the energy range 

from 100 to 500 keV. The energy spectral index in the transverse direction is noticeably less than in 

the longitudinal one. In the case of the longitudinal injection, two hard X-ray sources of different 

intensities and directivity are formed. The directivity of the emission from the loop top is opposite 

to the case of isotropic injection. This difference in the directivity can be used for the diagnostics of 

the pitch-angle distribution type of accelerated electrons.


P.7.37. A model of microwave and Sub-THz emission from 

a single flaring loop 

V.F. Melnikov 1,2 , J.E.R. Costa 3 and P.J.A. Simões 4 

1 Central Astronomical Observatory at Pulkovo of RAS, 196140, Saint-Petersburg, Russia 


3 Instituto Nacional de Pesquisas Espaciais, 12227-010, S.J.Campos, SP, Brazil 

4 Centro de Rádio Astronomia e Astrofísica Mackenzie, 01302-907, São Paulo, SP, Brazil 


The sub-THz component of solar flares is an emission observed in some flares as a secondary 

peak in the spectrum, typically above 100 GHz. Up to now, several mechanisms are suggested to 

explain this phenomenon. However, none of them can explain the full set of known properties of sub- 

THz emission and its relations to other emissions like microwave, hard X-ray etc. In this paper we 

search for specific reasonable conditions in flaring loops which allow to produce the sub-THz emission 

component in solar flares. We study in detail the gyrosynchrotron and free-free emission/absorption 

mechanisms under conditions of various non-stationary spatial distributions of relativistic electrons 

and plasma density/magnetic field distributions in magnetic loops. The proposed model is able to 

explain the appearence of the two spectral peaks (microwave and sub-THz) simultaneously, even 

from a single flaring loop, as well as the center-to-limb assymetry of sub-THz emission, and other 

observables. 

P.7.38. Magnetoacoustic wave trains in the decimetric 

radio events 

H. Mészárosová 1 

1 Astronomical Institute, Academy of Sciences, CZ-25165 Ondˇrejov, Czech Republic 


The periodicity of magnetoacoustic modes of propagating waves can be modified by the time 

evolution of an impulsively generated signal (e.g. by the impulsive flare process). We have studied 

these waves in decimetric radio spectra (2001 June 13 type IV event, 2005 July 11 event with fibers, 

group of 15 events with spikes) because they can provide us information about some parameters of 

the coronal loop (magnetoacoustic wave trains modulating gyrosynchrotrom emission of the radio 

source), neutral current sheet (wave trains modulating the radio emission produced by the plasma 

emission mechanism) and turbulent reconnection outflows (wave trains propagating through a source 

of the narrowband dm-spikes). 

P.7.39. The Coronal Mass Ejection index (Pi) and statistical 

properties of CMEs for the period Jan 1996 – Oct 2010 

E. Paouris 1 


University of Athens, Panepistimiopolis 15783 Zografos, Athens, Greece 


Coronal Mass Ejections (CMEs) are powerful eruptions and represent a very important factor 

for the solar activity even in periods of solar minimum and sometimes with devastating results for 

satellites, communication and electricity networks and astronauts or space missions in general. In


this work we are calculating the statistical index for the CMEs (E. Paouris, 2007) in relation with 

the variation of density for cosmic rays with 10 GV rigidity and we are studying the 23rd solar cycle 

in three phases: ascending, maximum and descending and also the beginning of the 24th solar cycle. 

We are studying also a lot of statistical properties of CMEs as individual or sometimes in relation 

to each other like: the mean linear speed Vp per month and over Carrington rotation cycles, the 

number of CMEs Nc per month and over Carrington rotation cycles, the angular width, the central 

position angle and the source region of CMEs, the speed at 20 solar radii, the acceleration, and the 

CME rate per day. Moreover, we are studying the statistical properties of 409 HALO CMEs for the 

same period and finally we suggest the Pi-index as the main index for the determination of the solar 

activity contrary to the sunspot number. 

P.7.40. Study of narrow CMEs with large linear speeds 

during Solar Cycle 23 

I. Patsou 1 ,P. Preka-Papadema 1 and X. Moussas 1 

1 Department of Physics, University of Athens 


The relation between Coronal Mass Ejections (CMEs) and the other manifestations of solar activity 

remains an open issue. In this work we have focused on CMEs with angular widths less than 

20 o (narrow CMEs) and we investigate possible association between narrow CMEs and solar flares 

for the period 1996-2007. It is noticeable that ∼80% of narrow CMEs is not associated with flares, 

within a time span of 2 hours centered at the CME onset (linearly determined “onset1“). Moreover, 

the temporal evolution of narrow CMEs is not consistent with the decline towards solar minimum. 

Instead, their number gradually increases after 2003 and peaks in the year 2007. Additionally, the 

distribution on the solar disk and the physical parameters of narrow CMEs were studied. Furthermore, 

very few (∼1.2%) narrow CMEs are fast with linear speeds greater than 1000 km/sec. In this 

paper we examined the relation of this category with radio emissions. Narrow CMEs with large linear 

speeds that are associated temporarily and spatially with simultaneous flares (∼15%) are mostly 

(∼80%) accompanied by simultaneous type III G radio bursts emanating from the coronal base and 

extending to interplanetary space. The majority of narrow CMEs with large linear speeds (∼70%) 

are not associated with either flares or radio emission. Approximately ∼22% are temporarily associated 

with isolated type III radio bursts stemming from high coronal levels. A small percentage 

(∼7.5%) are complex events where a unique association with only one type III radio burst was not 

possible. We should mention that this is still a work in progress. More thorough study is required to 

understand the relation between this special category of narrow CMEs and type III radio bursts. 

P.7.41. Analysis of MHD simulation results for the purpose 

of search of X-ray solar flare sources 

A.I. Podgorny 1 , I.M. Podgorny 2 and N.S. Meshalkina 3 

1 Lebedev Physical Institute RAS, Leninsky Prospect, 53, Moscow 119991, Russia 

2 Institute of Astronomy RAS, Pyatnitskaya Street, 48, Moscow 119017, Russia 

3 Institute for Solar-Terrestrial Physics SO RAS, Lermontov Street, 126a, Irkutsk 664033, Russia 


For investigations the solar flare mechanism it is necessary to compare positions of flare sources 

obtained from MHD simulation with observations. All initial and boundary conditions for MHD 

equations are set from observations. The MHD simulation is performed in solar corona in numerical


domain as rectangular parallelepiped, which down boundary is situated on the photosphere and is 

contained the active region. The calculations are initiated several days before the flare when strong 

disturbances in the corona are absent, and so the potential magnetic field is used for setting initial 

conditions. To calculate the potential magnetic field the Laplace equation is solved numerically using 

oblique derivative boundary conditions, because in the general case the observed line-of-site magnetic 

field is tilted to photospheric boundary of numerical domain. To stabilize the numerical instabilities 

several numerical methods are developed and programming realized in the PERESVET code. The 

finite-difference scheme for MHD equations is absolutely implicit. The scheme is conservative relative 

to the magnetic flux. MHD simulation for the active region AR 10365 has shown formation of several 

current sheets. The system of visualization of MHD simulation results is developed. It has permits to 

find the form of current sheet in 3D space as the arc by analyzing of the current density distributions 

in several parallel planes crossed by the current sheet and by tracing magnetic lines in 3D space. 

The modernized graphical system is directed for searching of current sheet locations and definitions 

of the points of photosphere crossing with the magnetic lines which are going out of the current 

sheet. According to the solar flare electrodynamical model, these places are positions of sources of 

X-ray radiation. Such method permits to compare of MHD simulation results and results of X-ray 

measurements. 

P.7.42. Electrodynamical solar flare model based on energy 

accumulation in the current sheet magnetic field 

I.M. Podgorny 1 and A.I. Podgorny 2 

1 Institute of Astronomy RAS, Pyatnitskaya Street, 48, Moscow 119017, Russia 

2 Lebedev Physical Institute RAS, Leninsky Prospect, 53, Moscow 119991, Russia 


A solar flare occurs due to the explosive energy release in the corona above an active region, 

where the energy source may be only the magnetic field of electric currents. The 3D MHD numerical 

simulations show that energy accumulation occurs in the magnetic field of the current sheet, which 

is formed by slow (2-3 days) floating of a new magnetic flux in the active region. In numerical 

simulation any assumptions about the mechanism of flares are not done. The mechanism of flares 

is demonstrated by the results of numerical simulations using the real preflare state as initial and 

boundary conditions. The flare is a complex physical process with energy release up to 10 32 erg. 

The current sheet decay is accompanied by powerful burst of thermal and beam of X-ray emission, 

solar corona mass ejection ∼ 10 15 g, flux of relativistic protons, and radio emission. The prompt 

component of relativistic protons with the exponential spectrum is created inside the current sheet. 

It brings information about the mechanism of solar cosmic rays creation. Powerful flares (X class) 

arise over active regions after magnetic flux increasing up to 10 22 Max. No significant change of the 

magnetic flux in the active region during a flare is observed. That excludes any mechanism of solar 

flare appearance due to dissipation of the photospheric magnetic field. Several current sheets are 

created over a complicated active region before the set of powerful flares. Each of current sheets can 

be responsible for an elementary flare. For setting boundary conditions the maps of the photospheric 

magnetic field are used. The typical rate of reconnection estimated during a flare ∼ 10 7 cm/s. Solar 

flare is the universal phenomenon typical to stars, possessing the magnetic field. Only the Sun gives 

us possibility of detailed research this phenomena.


P.7.43. Solar Flares and Coronal Mass Ejections during 

23rd Solar Cycle 

P. Preka-Papadema 1 ,Th. Kouloumvakos 1 ,X. Moussas 1 ,G. Nikolaou 1 

and A. Theodoropoulou 1 

1 Department of Astrophysics,Astronomy and Mechanism, Faculty of Physics, University of Athens, Greece 


The rate occurrence and other characteristics of solar eruptive events, flares and CMEs, during 

the solar cycle 23 (1996-2007) is examined and time periods with intense solar activity is notified. 

The dependence of CME occurrence on their width, velocities and accelerations is studied. The 

flare number for each one of the GOES classification types and the flare occurrence by active region 

(A.R.) is also examined. Finally we study some sporadic periodicities of flares and CMEs timeseries 

using wavelet analysis. There is a diversification of the flare distribution, compared to the sunspot 

number after the last months of 2003. The years 2004 and 2005 seem to be more active in producing 

solar flares than during 2000-2002, while the A.R. appearance is in accordance with sunspot number 

occurrence. After January 2004 although active regions decrease, the production of flares increases 

while is due to small flares (type B, C). Moreover, there is an almost constant CMEs occurrence rate 

during 2003-2006 with a secontary maximum at 2005. The slow CMEs occurrence (¡300 km/sec) 

rises after December of 2003. Then, a further increase of the CMEs occurrence with a maximum 

caused by the narrow CMEs is observed during the solar minimum (2006-2007). The Halo CME rate 

increased too after the year 2003 while a second equally important peak to the one of solar maximum 

occurs during the years 2004-2005. Fast halo and partial halo CMEs have the tendency to decelerate. 

The occurrence of decelerated CMEs (¡-5m/s2) follows the solar cycle with a quasi-plateau after 2004 

and the occurrence of accelerated CMEs (¿ 5m/s2) as well almost constant speed CMEs exhibit a 

plateau after the solar maximum with an increasing trend and a secondary maximum near the solar 

minimum. Pearson correlation coefficient between Halo CMEs and flares is 0.77. 

P.7.44. Relationship between thermal and nonthermal 

components of microwave emission from a flaring loop 

V.M. Puzynya 1 , V.F. Melnikov 1,2 

1 Radiophysical Research Institute, 603950 Nizhny Novgorod, Russia 

2 Central Astronomical Observatory at Pulkovo of RAS, 196140 St-Petersburg, Russia 


The aim of this work is to study a spatial-temporal relationship between thermal and nonthermal 

components of the microwave emission in a single flaring loop. We analyze spectral and polarization 

properties of the loop microwave emission of the flare observed near the solar limb by Nobeyama Radioheliograph 

(NoRH) and Radio Polarimeters (NoRP). Data from GOES, SOHO/MDI, and RHESSI 

are also used for the analysis. The integrated (NoRP) burst time profile contains an impulsive peak 

and a successive gradual peak of the comparable amplitude. An analysis of series of NoRH images has 

shown that the source of impulsive peak is seen only in one footpoint of the flaring loop (northern), 

and its spectral slope between 17 and 34 GHz is rather high, α = −4. The gradual peak starts almost 

at the time of the impulsive peak maximum and reaches its maximum 8 min later. Its spectral slope 

is close to zero. These facts definitely indicate on the nonthermal origin of the impulsive peak and 

thermal free-free origin of the gradual one. It is also interesting that the gradual component starts 

simultaneously in both footpoints and delays 70-80 s in the upper part of the flaring loop. We give 

evidence in favor of the idea that during the impulsive peak, the precipitating nonthermal electrons 

heated chromosphere and then the evaporated plasma gradually filled in the whole loop and produced 

microwave and soft X-ray gradual burst from the whole body of the flaring loop.


P.7.45. Assessing a new method for deriving the Kinematics 

of ICMEs with a numerical simulation 

T. Rollett 1 , C. Möstl 1,2 , M. Temmer 1 , A.M. Veronig 1 , D. Odstrcil 3 

1 Institute of Physics, University of Graz, Universitätsplatz 5/II, 8010 Graz, Austria 

2 Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 

3 NASA/GSFC, Greenbelt, Maryland, USA 


The NASA STEREO mission offers the possibility to follow coronal mass ejections (CMEs) continuously 

on their way from the Sun through the inner heliosphere. The interpretation of the STEREO/ 

HI images, which provide wide-angle observations, is challenging. We use two different methods, 

Fixed-φ (Kahler and Webb, 2007) and Harmonic Mean (Lugaz, Vourlidas and Roussev, 2009), to 

calculate the kinematics of CMEs, which could be measured in situ from STEREO Behind or the 

Wind spacecraft at L1 and constrain the results in a novel way using the in situ arrival time and the 

measured solar wind bulk velocity. This approach provides constant propagation directions as well 

as the velocity profiles as a function of time and heliospheric distance. To test this new method we 

present first results of a comparison with synthetic HI images produced by the numerical MHD solar 

wind model ENLIL (Odstrcil and Pizzo, 2009), to see how well our method reproduces the real shape 

and dynamics of the modeled CME. 

P.7.46. Magnetic field line connectivity in the measurement of 

the magnetic helicity flux 

P. Romano 

INAF - Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania (ITALY) 


I show the importance of the magnetic connectivity determination in the measure of the magnetic 

helicity transport in an active region from the convention zone to the corona. Using MDI/SOHO 

full-disc line-of-sight magnetograms the horizontal velocities of the photospheric magnetic structures 

are estimated with the Differential Affine Velocity Estimator (DAVE) method and the approximation 

of the field line connectivity is determined by the potential field extrapolations. From these measures 

I estimate the time evolution of the twist and writhe components of the magnetic helicity transport. 

The correlation between the magnetic helicity accumulation and the solar eruption occurrence is 

outlined both taking into account the magnetic connectivity and neglecting it.


P.7.47. Radiative hydrodynamic simulation of solar flares and 

comparison with observations in Lyα and Hα 

F. Rubio da Costa 1 , F. Zuccarello 2 , N. Labrosse 3 , L. Fletcher 3 , 

M. Carlsson 4 , T. Prosecký 5 and J. Kaˇsparová 5 

1 Max-Planck Institut für Sonnensystemforschung, Max-Planck-Straße 2, 37191 Katlenburg-Lindau, Germany 

2 Università degli Studi di Catania. Dipartamento di Fisica e Astronomia. Via S. Sofia 78, 95123, Catania, Italy 

3 University of Glasgow. School of Physics and Astronomy. Glasgow, G12 8QQ, UK. 

4 Center of Mathematics for Applications, University of Oslo, P.O. Box 1053, Blindern, N-0316 Oslo, Norway 

5 Astronomical Institute of the Academy of Sciences of the Czech Republic, v. v. i., Fričova 298, 

25165 Ondˇrejov, Czech Republic 


In order to better understand the emission of solar flares at the chromospheric layer, we use 

RADYN (a radiative hydrodynamic code) to study the response of the atmosphere to the injection 

of a constant beam of non-thermal electrons at the apex of a 1D coronal loop, taking into account 

the heating from thermal soft X-ray emission. 

We compare the computed intensities with observations of solar flares during their impulsive phase 

in: 

• Lyα, using TRACE 1216 ˚A and 1600 ˚A data. 

• Hα, using data from the Multichannel Flare Spectrograph (MFS) - Ondrejov Observatory. 

We obtain a good agreement between the models and the observations, and discuss what we can learn 

about chromospheric flare diagnostics from these comparisons. 

P.7.48. True Velocities of Knots in Solar Prominences 

P. Rudawy 1 and M. Zapior 1 

1 Astronomical Institute of Wrocaw University, 51-622 Wrocaw, ul. Kopernika 11, Poland 


We compare true (3D) and projected (2D) velocities of knots in several solar prominences. The 

full velocity vectors of the prominences’ knots were measured using our unique method of restoration 

of the true three-dimensional (3D) trajectories of prominence knots using ground-based observations 

taken with a single telescope that is equipped with a Multi-Channel Subtractive Double Pass imaging 

spectrograph. We show that the 2D velocities of the prominences, established using filtergram 

observations with Lyot-type coronagraphs are a small fraction of the true full velocities of the matter 

only. 

P.7.49. Helicity Shedding in a Simulated CME 

N. Seehafer 1 , B. Kliem 1,2 and S. Rust 1 

1 Institute of Physics & Astronomy, University of Potsdam, Germany 

2 Mullard Space Science Lab., University College London, UK 


It has been suggested that coronal mass ejections remove the magnetic helicity of active regions 

from the Sun. Such removal is often regarded to be necessary due to the hemispheric sign preference 

of the helicity, which inhibits a simple annihilation by reconnection between volumes of opposite 

chirality. We have monitored the relative magnetic helicity contained in the coronal volume of a


simulated flux rope CME, as well as the upward flux of helicity through a horizontal plane in the 

simulation box. The unstable and erupting flux rope carries away only part of the initial helicity 

through the open upper boundary of the box; the larger part remains in the volume. We offer a 

simple physical explanation for this result. Since most active regions erupt only once in their lifetime, 

our finding suggests that the major part of the helicity which is transported into the corona by 

emerging active regions is redistributed into the coronal field upon the dispersal of the active regions 

and is eventually transported back into the solar interior as the field submerges. 

P.7.50. Sweet–Parker current sheet and the onset of 

impulsive bursty reconnection 

Marina Skender 1 and Giovanni Lapenta 2 

1 Hvar Observatory, University of Zagreb, Kačićeva 26, Zagreb HR–10000, Croatia 

2 Centrum voor Plasma Astrofysika, KU Leuven, Celestijnenlaan 200B bus 2400, Leuven 3001, Belgium 


A Sweet–Parker current sheet is studied numerically in the MHD approximation utilising a particle 

in cell code. Different simulation setups are employed in order to follow the evolution of the formed 

current sheet in diverse configurations: Two types of initial equilibria, Harris and force–free, two types 

of boundary conditions, periodic and open, with uniform and non–uniform grid set, respectively. All 

the simulated cases are found to exhibit qualitatively the same behavior in which a current sheet 

evolves slowly through a series of quasi-equilibria; eventually it fragments and enters a phase of fast 

impulsive bursty reconnection. At the adopted Lundquist number of S = 10 4 and Reynolds number 

R = 10 4 , the aspect ratio of the formed current sheet is observed to increase slowly in time up to 

a maximum value at which it fragments. Additional turbulence applied to the system is shown to 

exhibit the same qualitative steps, but with the sooner onset of the fragmentation and at smaller 

aspect ratio. 

P.7.51. Understanding the implications of the presence of 

internal current sheets for the large-scale topology of ICMEs 

K. Steed 1 , G. Lapenta 1 and C. J. Owen 2 

1 Centre for Plasma Astrophysics (CPA), K. U. Leuven, Celestijenlaan 200B bus 2400, B-3001 Leuven, Belgium 

2 Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey, RH5 6NT, UK 


As a magnetic cloud passes over a spacecraft located in the solar wind, a bipolar signature, 

observed in the azimuthal magnetic field component, is anticipated. This is indicative of the largescale 

rotation of the magnetic field within the structure. However, this rotation is not always smooth, 

and often exhibits both small- and large-scale fluctuations of the magnetic field within the cloud. 

Within this substructure, current sheets are frequently observed. Here, we study these features, 

in detail, with a view to better understanding their origins; are they present during the eruption of 

a CME, or do they form during the subsequent evolution of the magnetic structure as it propagates 

into interplanetary space? 

We also investigate the process of magnetic reconnection within the observed current sheets, for 

which we find some evidence in the form of possible reconnection exhausts with signatures in both the 

in situ magnetic field and plasma observations. We consider what role, if any, magnetic reconnection 

plays in determining the large-scale topology of a magnetic flux rope.


P.7.52. On the initiation of Coronal Mass Ejections observed 

by STEREO/EUVI. 

P. Syntelis 1 , K.Tsinganos 2,3 , A. Vourlidas 4 and C. Gontikakis 1 

1 Research Center for Astronomy and Applied Mathematics, Academy of Athens, Soranou Efessiou St 4, 

11527 Athens, Greece 

2 Section of Astrophysics, Astronomy & Mechanics Department of Physics, University of Athens, 

Panepistimiopolis 157 84, Zografos, Greece 

3 National Observatory of Athens, P.O. BOX, 20048, Thissio-11810,Athens, Greece 

4 Solar Physics Branch, Space Sciences Division, Naval Research Laboratory, Washington, DC 20375, USA 


We study the initiation of a Coronal Mass Ejection’s (CME) in NOAA Active Region (AR) 10980, 

observed on January 2, 2008 by STEREO’s Extreme UltraViolet Imager (EUVI) at 171˚A. We identify 

a first phase consisting of an upward motion, which at 1.58R⊙ reaches a speed of 70kms −1 . These 

measurements are extrapolated to later time frames to examine whether this initial acceleration 

drives the CME’s propagation later on. We also identify an ascending new flux-rope beneath the 

CME. During the CME’s rise, there are indications that some adjacent loops are inclined to the main 

CME body. At the later phase of the initiation, some moving blob-like structures appear along the 

CME flanks. Propagation speeds of these blobs are measured. The blobs could be indications that a 

siphon flow exists along the CME. 

P.7.53. Toroidal models and magnetic-cloud observations 

M. Vandas 1 and E. P. Romashets 2 

1 Astronomical Institute, Academy of Sciences, Prague, Czech Republic 

2 Solar Observatory, Prairie View A&M University, Prairie View, TX 77446, USA 


Magnetic clouds are solar ejecta with special properties. They are part of coronal mass ejections, 

the part with shaped magnetic field in a form of a flux rope. Magnetic clouds propagate in the solar 

wind, and reaching Earth, they may trigger severe geomagnetic storms. Usually magnetic clouds are 

locally modelled by a straight cylindrical flux rope. In the present analysis, toroidal flux-rope models 

are used to interpret magnetic-cloud in-situ observations. Parameters following from cylindrical 

and toroidal models are compared and it is investigated which of them are more appropriate. To 

accomplish this task, in addition to solar wind magnetic field data, also plasma data (namely velocity) 

are taken into account in our analysis. 

P.7.54. Influence of static and stochastic electric fields on 

electron beams bombarding the chromosphere. 

M. Varady 1,2 , M. Karlický 2 and Z. Moravec 1 

1 Purkyně University, Faculty of Science, Ústí nad Labem, Czech Republic 

2 Astronomical Institute, Academy of Sciences, Ondˇrejov, Czech Republic 


Using a test-particle approach we study the influence of static and stochastic electric fields on 

propagation of electron beams along the magnetic fieldlines from the primary acceleration site in 

the coronal current sheets downwards to the chromosphere. The results are compared with the most 

common, classical model of electron beam propagation, scaterring and thermalisation given by Emslie 

(1978) and the effects in chromospheric heating and hard X-ray emission are discussed.


P.7.55. RHD models of solar flares 

M. Varady 1,2 , Z. Moravec 1 , J. Kaˇsparová 2 , P. Heinzel 2 and M. Karlický 2 

1 Purkyně University, Faculty of Science, Ústí nad Labem, Czech Republic 

2 Astronomical Institute, Academy of Sciences, Ondˇrejov, Czech Republic 


In the context of interpreting the non-thermal hard X-ray emission and γ lines emanating from 

the footpoints of flare loops, most contemporary flare models assign a fundamental role during the 

flare energy release, transport and deposition to the high energy non-thermal particle beams. In 

our contribution we concentrate on RHD modelling of the spectroscopic properties of chromospheric 

flare emission in optical hydrogen lines generated due to the bombardment of the chromosphere and 

photosphere by particle beams with power-law spectra. 

P.7.56. Relation between CME and nonthermal flare 

characteristics 

A.M. Veronig 1 , S. Berkebile-Stoiser 1 , B. Bein 1 , M. Temmer 1 , N. Stevanecz 1 

1 Institute of Physics, University of Graz, Austria 


We study the relation between the nonthermal emission of solar flares and characteristic parameters 

describing the evolution of the associated CME using SOHO/LASCO, STEREO/EUVI&COR 

and RHESSI observations. Flare parameters include the hard X-ray spectral index and flux, the 

number of accelerated electrons and the kinetic energy in electrons. Characteristic CME parameters 

include velocity, peak acceleration, height and duration of peak acceleration, and initiation height. 

We find a distinct trend that fast CMEs with impulsive acceleration are correlated with harder hard 

X-ray spectra and higher electron fluxes. The CME kinetic energy and the energy in flare-accelerated 

electrons are distinctly correlated and are of the same order of magnitude. 

P.7.57. Magnetic helicity balance during a filament eruption 

that occurred in active region NOAA 9682 

F. P. Zuccarello 1,2 , P. Romano 2 , F. Zuccarello 3 and S.Poedts 1 

1 Centre for Plasma-Astrophysics, K.U.Leuven, Celestijnenlaan 200B, 3001 Leuven, Belgium 

2 INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy 

3 Dipartimento di Fisica e Astronomia - Universitá di Catania Via S.Sofia 78, 95123 Catania, Italy 


Photospheric shear plasma flows in active regions may be responsible for the magnetic helicity 

injection in the solar corona not only during the energy storage process before a solar eruption, but 

also during and after the release of the free magnetic energy caused by the eruption. Indeed, after 

a filament eruption the magnetic torque imbalance can induce shear flows that can be responsible 

for yet another injection of magnetic helicity into the corona. We investigated the magnetic helicity 

balance in an active region where a confined solar eruption occurred. This was done to verify a 

possible relationship between the filament expansion and the helicity transport at its footpoints. We


aimed to verify if this variation in the helicity transport rate could be interpreted as a consequence 

of the magnetic torque imbalance caused by the tube expansion, as proposed by Chae et al. (2003). 

We used 171 ˚A TRACE data to measure some geometrical parameters of the new magnetic system 

produced by a filament eruption that occurred on 2001 November 1 in active region NOAA 9682. We 

used MDI full disk line-of-sight magnetogram data to measure the accumulation of magnetic helicity 

in the corona before and after the event. From the measured expansion factor in the magnetic 

arcade, visible at 171 ˚A during the eruption, we estimated that the resulting torque imbalance at the 

photosphere ought to lead to the injection of negative helicity following the eruption. We compared 

this with measurements of the helicity injection using photospheric velocity and magnetogram data. 

In contradiction to the expectations from the Chae et al. (2003) model, the helicity injection after 

the eruption was positive. We offer the alternative interpretation that the helicity injection resulted 

from torque of the opposite sign, generated as the filament lost its negative helicity through magnetic 

reconnection with its surroundings.


Session 8 

Origin and Properties of the Solar Wind 

P.8.1. Outflows overlying SG network and coronal hole 

structures 

Alan Gabriel 1 and Lucia Abbo 2 

1 Institut d’Astrophysique Spatiale, Université Paris-Sud 11, 91405 Orsay, France 

2 Osservatorio Astronomico di Torino, Pino Torinese 10025 - Italy 


We have derived outflow velocity maps in the quiet Sun from EIS/Hinode, over a range of coronal 

and TR temperatures. These are used in order to study effects due to the underlying supergrannule 

network and of coronal holes. To identify clearly the SG network and its associated magnetic structure, 

we have used data from SDO; specifically 1600 ˚A images from AIA and magnetic fields and 

velocitigrams from HMI. Our observations, together with others published previously (eg Hassler et 

al., Science 1999), are interpreted in terms of the magnetic field of the network in the transition 

region, involving the release of energy and leading to the solar wind outflow. 

P.8.2. 23rd solar cycle: wavelet analysis on solar wind 

parameters 

Ch. Katsavrias, P. Preka - Papadema and X. Moussas 

Section of Astrophysics, Astronomy and Mechanism, Dept of Physics, University of Athens, Greece 


The sun as an oscillator produces frequencies which propagate in the heliosphere via solar wind. 

We searched for those frequencies in the parameters of the solar plasma near Earth for the past 

three solar cycles. We found out that each parameter of the solar wind carries certain periodicities 

which differentiate in each cycle. We also found a similar behavior between 21st and 23rd cycle in all 

parameters.Please fill in the text of your abstract here.


P.8.3. New Developments in Exospheric Theory of the Solar 

Wind 

G. Le Chat 1 , H. Lamy 2 , V. Pierrard 2,3 , N. Meyer-Vernet 1 , K. Issautier 1 , 

M. Maksimovic 1 and I. Zouganelis 4 

1 LESIA, Observatoire de Paris, CNRS, UPMC, Université Paris Diderot; 5 Place Jules Janssen, 92195 Meudon, France 

2 Belgian Institute for space Aeronomy, Space Physics, av. circulaire 3, 1180 Brussels, Belgium 

3 Center for Space Radiations, Institute of Research in Mathematics and Physics, Universit Catholique de Louvain, 

chemin du cyclotron 2, 1348 Louvain-La-Neuve, Belgium 

4 Laboratoire de Physique des Plasmas, UPMC, Ecole Polytechnique, CNRS, Univ. Paris 11, 4 avenue de Neptune, 

94107 Saint-Maur-des-Fosss, France 


Due to the rare collisions, kinetic collisionless models have been extensively used to describe the 

solar wind. In these models, the solar wind acceleration is driven by the radial electric field needed 

to maintain the quasineutrality of the plasma because of the large proton-to-electron mass ratio. The 

last generations of exospheric models have improved the agreement with observations of slow and fast 

solar wind by using non-thermal electron velocity distributions, as observed in the solar wind. We 

present the results of latest developments of the exospheric models. These developments show the 

role of the trapped particles, of the proton temperature anisotropy and of the Parker’s spiral in the 

solar wind acceleration process. 

P.8.4. 3D PIC modeling of particle acceleration in HCS and 

its effect on the definition of sector boundaries 

V.V.Zharkova 1 and O.Khabarova 2 

1 Department of Mathematics, School of Computing, Informatics and Media, University of Bradford, 

Bradford BD7 1DP, UK 

2 Heliophysical Laboratory, Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation RAS (IZMIRAN), 

Troitsk, Moscow region, 142190, Russia 


In the current paper we investigate with full kinetic particle-in-cell (PIC) approach the conditions 

of particle acceleration in a current sheet with the conditions of helispheric current sheet(HCS) for a 

magnetic field configuration deduced from observations. We present electron and proton trajectories, 

angle and energy distributions inside HCS for different magnetic field topologies and compare these 

with available measurements. As result, we managed (1) to reproduce the distribution across the 

current sheet and beyond of the simulated polarisation electric field induced by protons and electrons 

accelerated in this current sheet and separated with respect to the sector boundary into the opposite 

semiplanes which remarkably resembles the distributions of ion velocities measured about the sector 

boundary. (2) In addition, simulations reveal that the measured ion charge distributions across the 

heliospheric current sheet is to be defined by distributions of protons (ions) being accelerated during 

a magnetic reconnection. (3) At the same time for some HCS parameters energetic electrons can 

appear far away from the HCS midplane moving towards and from current sheet while (4) creating 

significant Langmuir turbulence. This study opens new perspectives for understanding processes in 

the vicinity of HCS and for diagnostics of the sector boundaries in relation to magnetic reconnection 

scenarios derived from the measurements of accelerated particle parameters.


Session 9 

Solar Data Assimilation and Space Weather Research 

P.9.1. Heliospheric Modulation of Primary Cosmic Rays: 

Approximation model 

M. Buchvarova 

Space and Solar-Terrestrial Research Institute-BAS, 6 Moskovska Str., Sofia 1000, Bulgaria; marusjab@yahoo.com 


An analytical model which generalizes the differential galactic cosmic ray spectrum in the heliosphere 

is proposed. The model parameterizes the spectrum at different physical conditions, including 

the most important effects controlling the CR intensity like diffusion - convection and energy losses. 

By a suitable choice of fitted parameters proposed model turns into two approximations: solution 

close to force - field” model (describing the energy losses of CR in the in the inner heliosphere) and 

convection-diffusion” equation (giving the reduction of CR intensity in the outer heliosphere). A 

general relationship between the parameters on the model and the modulation potential is derived. 

It is shown this model is more flexible to the data fitting than force - field approximation. The 

dependence of the model parameters on the solar activity parameters is discussed. 

P.9.2. Simulation of Altitude Variation of Aerosol 

Production during Solar Cycle 

D. T. Draganov 1 , M. Buchvarova 1 

1 Space and Solar-Terrestrial Reseach Institute, BAS, 6 Moskovska St,. Sofia 1000, Bulgaria 


To further evaluate GCR-cloud link it is proposed a computational simulation of altitude variation 

of stratospheric and tropospheric ultra fine aerosol production during the 11-year solar cycle on the 

base of ion-nucleation mechanism. The computational simulations in the troposphere are based 

on ion-mediated nucleation (IMN) theory [1],[2]. The stratospheric ultra fine aerosol particles are 

calculated with the equation of Hofman and Rosen [3]. To the parameters controlling the particle 

formation (ambient conditions and altitude) ion-nucleation theory adds ion concentration. In the 

proposed computer model the ionization is estimated with Corsika Code Simulations.


P.9.3. Shock Wave Formation in Cometary Dusty Plasma 

Z. Ehsan 1 , S. Ghosh 2 and S. Poedts 1 

1 Center for Plasma Astrophysics, K. U. Leuven, Celestijnenlaan 200B, 3001, Leuven, Belgium. 

2 Department of Applied Mathematics University of Calcutta, West Bengal, India. 


Dusty plasmas with negative ions, i.e., electronegative dusty plasmas are quite obvious in astrophysical 

cometary plasma as well as in modern technological applications. The linear collective 

phenomena, the spatial profiles of number densities of electrons, positive ions, electrons temperature, 

and dust charge are investigated in electronegative dusty plasma. Horanyi and Mendis calculated 

the trajectories of micron and submicron sized dust grains that are expected to be released from 

the cometary nucleus. It was shown that the electromagnetic forces associated with the motion of 

the grains which are electrically charged by virtue of plasma environment through the magnetized 

plasma played a crucial role in their dynamics. Different spacecrafts (Vega 1, Vega 2, and Giotto) 

observations on comets reveal that Comet Halley contains electrons, ice dust grains, and different 

positive and negative ions such as (H+,H), (O+,O), (Si+,Si), (OH+,OH), and etc. For the numerical 

analysis of the present findings, (H+,H) and pure ice dust grains are to be considered. Here the effects 

of nonsteady dust charge variations and weak magnetic field on small but finite amplitude nonlinear 

dust acoustic wave in electronegative dusty plasma are investigated. The dynamics of the nonlinear 

wave are governed by a Kortewegde Vries Burger equation that possesses dispersive shock wave. The 

weak magnetic field is responsible for the dispersive term, whereas nonsteady dust charge variation 

is responsible for dissipative term, i.e., the Burger term. The coefficient of dissipative term depends 

only on the obliqueness of the magnetic field. It is found that for parallel propagation the dynamics 

of the nonlinear wave are governed by the Burger equation that possesses monotonic shock wave. 

The relevances of the findings to cometary dusty plasma, e.g., Comet Halley are briefly discussed. 

P.9.4. FPGA based spectral correlator for Siberian Solar 

Radio Telescope 

A.V. Gubin 1 , S.V. Lesovoi 1 

1 Institute of Solar-Terrestrial Physics, Irkutsk, Russia 


We present an FPGA implementation of multi-channel correlator for radio astronomy applications, 

namely for the Siberian Solar RadioTelescope (SSRT). The correlator is based on the Altera Stratix 

IV GX FPGA Development Kit and is implemented as peripheral device connected to a NIOS II 

system. Altera Quartus II is used as the main development tool. 

In order to use a SSRT data acquiring sofware it is necessary to record the autocorrelation of the 

sum and difference of North-South and East-West antenna array signals. In such a way, a compatibility 

with the existing acousto-optical receiver is provided. The correlator has 256 lags(channels) 

and frequency bandwidth of 130 MHz. To achieve the desired band we use parallelization of the data 

flow by the factor of 3 that consequently results in 3 times increase of MAC operations equally. This 

approach allows simultaneous execution of several computational operations during one clock cycle 

and is an effective approach for acceleration. 

One of the important features of the developed correlator is that it uses dedicated digital signal 

processing (DSP) blocks designed for performing DSP operations in real-time at higher speeds 

compared with the implementation of computation on the logic cells. The developed correlator uses 

1264 16 bit DSP blocks that occupy 98% of the whole chip (EP4SGX230KF40C2). Data acquiring 

is performed by two Texas ADC (ADS5463EVM evaluation kit) through on-chip LVDS transceivers. 

Further, the correlator data, through ethernet, are written into PC HDD. Finally, the proposed 

correlator can be used in any task of obtaining the spectrum in real time, e.g. for the solar radio 

spectrometers.


P.9.5. Comparison of sunspot and white light facular areas 

derived from SOHO/MDI and SDO/HMI imagery 

L. Győri 

Konkoly Observatory, Gyula Observing Station, 5701 Gyula, Po.Box 93, Hungary 


Among the characteristics of the solar activity are the areas on the solar surface, covered by 

sunspots and white light faculae. The measured sunspots and white light facular areas are used in 

many fields of Solar Physics studies (e.g., solar irradiance, solar cycle, periodicities in solar activity, 

and sunspot development). We determined sunspot and white light facular areas with the same 

image processing method SAM (Sunspot Automatic Measurement) developed at the Heliophysical 

Observatory at Debrecen, in images taken by the SOHO/MDI and SDO/HMI instruments nearly at 

the same time. We found a significant difference in the two feature areas between the two image 

sets, especially in the case of the white light faculae. This difference can be explained by the major 

difference in image resolution between SOHO/MDI and SDO/HMI images. 

P.9.6. JHelioviewer: Open-Source Software for Discovery and 

Image Access in the Petabyte Age 

D.Müller 1 , G. Dimitoglou 2 , M. Langenberg 3 , M. Nuhn 3 , J.P. Garcia Ortiz 4 , 

A. Dau 5 , S. Pagel 6 , L. Schmidt 7 , V.K. Hughitt 8 , J. Ireland 8 and B. Fleck 9 

1 Research and Scientific Support Department, ESA/ESTEC, Noordwijk, Netherlands 

2 Department of Computer Science, Hood College, Frederick, MD, USA 

3 RTWH Aachen, Germany 

4 University of Almeria, Almeria, Spain 

5 Technical University of Munich, Germany 

6 University of Applied Sciences (HTW) Berlin, Germany 

7 University of Cambridge, Cambridge, United Kingdom 

8 ADNET Systems Inc., Greenbelt, MD, USA 

9 Science Operations Department, ESA c/o NASA GSFC, Greenbelt, MD, USA 


The unprecedented torrent of data returned by the Solar Dynamics Observatory is both a blessing 

and a barrier: a blessing for making available data with significantly higher spatial and temporal 

resolution, but a barrier for scientists to access, browse and analyze them. With such staggering data 

volume, the data is bound to be accessible only from a few repositories and users will have to deal with 

data sets effectively immobile and practically difficult to download. From a scientist’s perspective this 

poses three challenges: accessing, browsing and finding interesting data while avoiding the proverbial 

search for a needle in a haystack. 

To address these challenges, we have developed JHelioviewer, an open-source visualization software 

that lets users browse large data volumes both as still images and movies. We did so by deploying an 

efficient image encoding, storage, and dissemination solution using the JPEG 2000 standard. This 

solution enables users to access remote images at different resolution levels as a single data stream. 

Users can view, manipulate, pan, zoom, and overlay JPEG 2000 compressed data quickly, without 

severe network bandwidth penalties. Besides viewing data, the browser provides third-party metadata 

and event catalog integration to quickly locate data of interest, as well as an interface to the Virtual 

Solar Observatory to download science-quality data. 

As part of the Helioviewer Project, JHelioviewer offers intuitive ways to browse large amounts of 

heterogeneous data remotely and provides an extensible and customizable open-source platform for 

the scientific community.


P.9.7. The asymptotic longitudinal cosmic ray intensity 

distribution as precursor for Forbush decreases 

M. Papailiou 1 , H. Mavromichalaki 1 , A. Belov 2 , E. Eroshenko 2 

and V. Yanke 2 

1 Nuclear and Particle Physics Section, Physics Department, National and Kapodistrian University of Athens, 15771 

Athens Greece 

2 Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation RAS (IZMIRAN), Troitsk, 

Moscow region, Russia 


Identifying the precursors (pre-increases or pre-decreases) preceding a geomagnetic storm or a 

Forbush decrease is of great importance since they can forecast and provide warning about the 

oncoming space weather effects. In this particular study four Forbush decreases (June 24, 1980, 

October 28, 2000, August 17, 2001 and May 10, 2002) have been analyzed. These events were chosen 

from a list of events, which occurred in the years from 1967 to 2006 with an anisotropy Axy > 

1.2%. Apart from hourly cosmic ray intensity data, provided by the world-wide network of neutron 

monitor stations, data on solar flares, solar wind speed, geomagnetic indices (Kp and Dst) and 

interplanetary magnetic field were used for the analysis of the aforementioned cosmic ray intensity 

decreases. Moreover the asymptotic longitudinal cosmic ray distribution diagrams were plotted using 

the Ring of Stations method. Results reveal a long pre-decrease up to 20hrs before the shock arrival 

in a narrow longitudinal zone from 90 o to 180 o . 

P.9.8. Solar Energetic Particles on a heliospheric scale: A 

Ulysses event list over solar cycle 23 

A. Papaioannou 1,2 , O.E. Malandraki 1 and K. Tziotziou 1 

1 Institute of Astronomy and Astrophysics, National Observatory of Athens, Greece 

2 Nuclear and Particle Physics Section, Physics Department, National and Kapodistrian University of Athens, Greece 


The Ulysses spacecraft, due to its eccentric orbit over the solar poles and its continuous presence in 

space for 18 years, has been the only solar mission so far that allowed us to study the characteristics 

of Solar Energetic Particles (SEPs) at low and high lalitudes and their distribution over a solar 

cycle. The intensities of SEPs are strongly affected by the variations in the level of solar activity, 

the characteristics of the solar wind and the properties of the interplanetary magnetic field that 

enable the acceleration and propagation of SEPs throughout the heliosphere. The study of SEPs 

at different latitudes and under different heliospheric conditions provides useful information about 

the global structure of the heliosphere during solar minimum and solar maximum, as well as on the 

mechanisms and the physics of solar particle genesis, propagation and acceleration. In this work, two 

instruments onboard Ulysses have been used in order to identify all SEPs observed in and out of the 

ecliptic plane, namely: the Heliosphere Instrument for Spectra, Composition and Anisotropy in Low- 

Energies (HI-SCALE) and the Low-Energy Telescope (LET) of the Cosmic Ray and Solar Particle 

Investigation (COSPIN). A scan over solar cycle 23 has been performed on the low-energy protons of 

COSPIN/LET (energy range: 0.9-8.0 MeV) and the Deflected Electrons (DEs) of HI-SCALE (energy 

range: 38-315 keV). As a result, a list of about 150 well-defined events has been compiled. A part 

of this list, together with the analysis of several case studies and their association to possible solar 

sources, is being discussed. Further, ongoing work, includes the single treatment of each event and 

the identification of its solar source. This could serve as the basis for future solar missions, such as 

Solar Orbiter - in which IAA/NOA participates as a Co-Investigator (EPD instrument).


P.9.9. PROGNOSIS: a web based environment for monitoring 

of solar activity based on microwave observations 

S.Kh. Tokhchukova 1 , T.I. Kaltman 1 and V.M. Bogod 1 

1 St.Petersburg Department of SAO RAS 


We are developing a web based data analysis system PROGNOSIS for monitoring of solar activity 

based on multi octave microwave observations with RATAN-600 radio telescope in combination with 

data from other solar observatories available on the Internet. 

The system performs automated collection of data, quality control, and pre-processing. It provides 

interactive IDL/ION web applications for the automated interactive data analysis, visualization, and 

modeling, to study physical processes in wide height ranges of solar atmosphere. 

Developed methods for plasma parameters calculation and spatial/temporal/spectral features 

recognition create a basis for developing of an automated powerful solar flares forecasting tool.


List of participants (in alphabetical order)


.

Name Affiliation - email Country 

Abakumov, Ivan 

St.Petersburg State University 

abakumov_ivan@mail.ru 

Afanasyev, Andrey Institute of Solar-Terrestrial Physics 

afa@iszf.irk.ru 

Al-Haddad, Nada K.U. Leuven 

nadaa@gmail.com 

Alissandrakis, Costas University of Ioannina 

calissan@cc.uoi.gr 

Altyntsev, Alexander Institute of Solar-Terrestrial Physics, SD RAS 

altyntsev@iszf.irk.ru 

Alvarado Gomez, Julian David Universidad Nacional de Colombia 

raikoh1480@gmail.com 

Andretta, Vincenzo Osservatorio Astronomico di Capodimonte, INAF 

andretta@oacn.inaf.it 

Andries, Jesse K.U. Leuven 

jesse.andries@wis.kuleuven.be 

Antiochos , Spiro NASA Goddard Space Flight Center 

spiro.antiochos@nasa.gov 

Antolin, Patrick University of Oslo 

antolin@astro.uio.no 

Antonucci, Ester Osservatorio Astronimico di Torino, INAF 

antonucci@oato.inaf.it 

Archontis, Vasilis University of St Andrews 

vasilis@mcs.st-and.ac.uk 

Arregui, Inigo Universitat de les Illes Balears 

inigo.arregui@uib.es 

Asensio Ramos, Andres Instituto de Astrofisica de Canarias 

aasensio@iac.es 

Auchere, Frederic Institut d'Astrophysique Spatiale 

frederic.auchere@ias.u‐psud.fr 

Avramenko, Evgeniya St.Petersburg State University 

avramenko04@mail.ru 

Battaglia, Marina 

University of Glasgow 

marina.battaglia@glasgow.ac.uk 

RUSSIA 

RUSSIA 

BELGIUM 

GREECE 

RUSSIA 

COLOMBIA 

ITALY 

BELGIUM 

USA 

NORWAY 

ITALY 

UK 

SPAIN 

SPAIN 

FRANCE 

RUSSIA 

UK 

165

Baumann, Gisela University of Copenhagen 

gbaumann@nbi.dk 

Bein, Bianca University of Graz 

bianca.bein@uni‐graz.at 

Belik, Marcel Observatory Upice 

belik@obsupice.cz 

Bellot Rubio, Luis Ramon Instituto de Astrofisica de Andalucía – CSIC 

lbellot@iaa.es 

Bethge, Christian High Altitude Observatory 

bethge@ucar.edu 

Bian, Nicolas Glasgow University 

nbian@hotmail.com 

Bingert, Sven Max Planck Institute for Solar System Research 

bingert@mps.mpg.de 

Bloomfield, D. Shaun Trinity College Dublin 

shaun.bloomfield@tcd.ie 

Bogod, Vladimir Special Astrophysical Observatory 

vbog@sao.ru 

Borrero, Juan Manuel Kiepenheuer-Institut für Sonnenphysik 

borrero@kis.uni‐frieburg.de 

Bourantzis, Costas University of Athens 

kbouratz@phys.uoa.gr 

Bourdin, Philippe Max Planck Institute for Solar System Research 

Bourdin@MPS.mpg.de 

Brandenburg, Axel Nordic Institute for Theoretical Physics (Nordita) 

brandenb@nordita.org 

Buchvarova, Marusya Bulgarian Academy of Sciences 

marusjab@yahoo.com 

Burge, Christina University of Glasgow 

c.burge@astro.gla.ac.uk 

Carbonell, Marc Universitat Illes Balears 

marc.carbonell@uib.es 

Cauzzi, Gianna Osservatorio Astrofisico di Arcetri, INAF 

gcauzzi@arcetri.astro.it 

Collados, Manuel Instituto de Astrofisica de Canarias 

mcv@iac.es 

DENMARK 

AUSTRIA 

166 

CZECH REPUBLIC 

SPAIN 

USA 

UK 

GERMANY 

IRELAND 

RUSSIA 

GERMANY 

GREECE 

GERMANY 

SWEDEN 

BULGARIA 

UK 

SPAIN 

ITALY 

SPAIN

Criscuoli, Serena Osservatorio Astronomico di Roma, INAF 

serena.criscuoli@oa‐roma.inaf.it 

Curdt, Werner Max-Planck-Institut für Sonnensystemforschung 

curdt@mps.mpg.de 

Dadashi, Neda Max Planck Institute for Solar System Research 

dadashi@mps.mpg.de 

Danilovic, Sanja Max-Planck-Institut für Sonnensystemforschung 

danilovic@mps.mpg.de 

Dara, Helen RCAAM, Academy of Athens 

edara@academyofathens.gr 

Davey, Alisdair Harvard Smithsonian Center for Astrophysics 

ard@head.cfa.harvard.edu 

De Groof, Anik Royal Observatory of Belgium-ESA 

anik.degroof@esa.int 

De la Luz Rodriguez, Victor 

Hugo 

De Moortel, Ineke University of St Andrews 

ineke@mcs.st‐and.ac.uk 

Instituto Naciona de Astrofisica Optica y Electronica 

itztli@gmail.com 

De Pontieu, Bart Lockheed Martin Solar & Astrophysics Laboratory 

bdp@lmsal.com 

Demidov, Mikhail Institute of Solar-Terrestrial Physics 

demid@iszf.irk.ru 

Dickson, Ewan University of Glasgow 

e.dickson@physics.gla.ac.uk 

Doerr, Hans-Peter Kiepenheuer-Institut für Sonnenphysik 

doerr@kis.uni‐freiburg.de 

Dudík, Jaroslav Comenius University 

dudik@fmph.uniba.sk 

Dzifcakova, Elena Astronomical Institute 

elena@asu.cas.cz 

Ehsan, Zahida K.U. Leuven 

Zahida.Ehsan@wis.kuleuven.be 

Eselevich, Maxim Institute of Solar-Terrestrial Physics 

mesel@iszf.irk.ru 

Faurobert, Marianne University of Nice 

marianne.faurobert@unice.fr 

ITALY 

GERMANY 

GERMANY 

GERMANY 

GREECE 

USA 

BELGIUM 

MEXICO 

UK 

USA 

RUSSIA 

UK 

GERMANY 

SLOVAKIA 

167 


BELGIUM 

RUSSIA 

FRANCE

Filippov, Boris IZMIRAN 

bfilip@izmiran.ru 

Fleck, Bernard Science Operations Department-ESA 

bfleck@esa.nascom.nasa.gov 

Franz, Morten Kiepenheuer-Institut für Sonnenphysik 

morten@kis.uni‐freiburg.de 

Gabriel, Alan Institut d'Astrophysique Spatiale 

alan.gabriel@ias.u‐psud.fr 

Ganse, Urs University of Wuerzburg 

uganse@astro.uni‐wuerzburg.de 

Georgoulis, Manolis RCAAM, Academy of Athens 

manolis.georgoulis@academyofathens.gr 

Gimenez de Castro, Guillermo Universidade Presbiteriana Mackenzie 

guigue@craam.mackenzie.br 

Gontikakis, Costis RCAAM, Academy of Athens 

cgontik@academyofathens.gr 

Goossens, Marcel K.U. Leuven 

Marcel.Goossens@wis.kuleuven.be 

Gordovskyy, Mykola University of Manchester 

mykola.gordovskyy@manchester.ac.uk 

Grigoryeva, Irina Central Astronomical Observatory at Pulkovo of RAS 

irina19752004@mail.ru 

Grimm, Oliver ETH Zurich 

oliver.grimm@phys.ethz.ch 

Gruszecki, Marcin Warwick University 

m.gruszecki@warwick.ac.uk 

Gubin , Alexey Institute of Solar-Terrestrial Physics 

gubin@iszf.irk.ru 

Guennou, Chloé Institut d'Astrophysique Spatiale, CNRS 

chloe.guennou@ias.u‐psud.fr 

Guerreiro, Nuno University of Oslo 

n.m.r.guerreiro@astro.uio.no 

Guglielmino, Salvo 

Instituto de Astrofisica de Canarias 

sgu@iac.es 

RUSSIA 

USA 

GERMANY 

FRANCE 

GERMANY 

GREECE 

BRASIL 

GREECE 

BELGIUM 

UK 

RUSSIA 

SWITZERLAND 

UK 

RUSSIA 

FRANCE 

NORWAY 

SPAIN 

168

Gyori, Lajos Konkoly Observatory of the Hungarian Academy of 

Sciences 

gylajos@tigris.unideb.hu 

Harra, Louise University College London 

lkh@mssl.ucl.ac.uk 

Higgins, Paul Trinity College Dublin 

pohuigin@gmail.com 

Huang, Zhenghua Armagh Observatory 

zhu@arm.ac.uk 

Inglis, Andrew NASA Goddard Space Flight Center 

andrew.inglis@nasa.gov 

Jacobs, Carla K.U. Leuven 

Carla.Jacobs@wis.kuleuven.be 

Jurcak, Jan Astronomical Institute, Academy of Sciences of the 

Czech Republic 

jurcak@asu.cas.cz 

Kallunki, Juha Aalto University 

kallunki@kurp.hut.fi 

Kaltman, Tatyana Special Astrophysical Observatory 

arles@mail.ru 

Katsavrias, Christos University of Athens 

ckatsavrias@gmail.com 

Khlystova, Anna Institute of Solar-Terrestrial Physics 

hlystova@iszf.irk.ru 

Khomenko, Elena Instituto de Astrofisica de Canarias 

khomenko@iac.es 

Kienreich, Ines Waltraud University of Graz 

ines.kienreich@uni‐graz.at 

Kilpua, Emilia University of Helsinki 

emilia.kilpua@helsinki.fi 

Klein, Karl-Ludwig Observatoire de Meudon 

ludwig.klein@obspm.fr 

Kleint, Lucia High Altitude Observatory 

kleintl@ucar.edu 

Kliem, Bernhard 

University of Potsdam 

bkliem@uni‐potsdam.de 

HUNGARY 

UK 

IRELAND 

UK 

USA 

BELGIUM 

169 


FINLAND 

RUSSIA 

GREECE 

RUSSIA 

SPAIN 

AUSTRIA 

FINLAND 

FRANCE 

USA 

GERMANY

Klimchuk, James NASA Goddard Space Flight Center 

James.A.Klimchuk@nasa.gov 

Klimeš, Jan Observatory Upice 

klimesml@obsupice.cz 

Klvana, Miroslav Astronomical Institute, Academy of Sciences of the 


mklvana@asu.cas.cz 

Kolobov, Dmitrii Institute of Solar-Terrestrial Physics, SB RAS 

kolobov@iszf.irk.ru 

Kontogiannis, Ioannis University of Athens 

jkonto@space.noa.gr 

Kotrc, Pavel Astronomical Institute, Academy of Sciences of the 


pkotrc@asu.cas.cz 

Kouloumvakos, Athanasios University of Athens 

athkouloumvakos@gmail.com 

Krivova, Natalie Max Planck Institute for Solar System Research 

natalie@mps.mpg.de 

Kunkel, Valbona George Mason University 

vkunkel@gmu.edu 

Kuzanyan, Kirill IZMIRAN 

kuzanyan@gmail.com 

Labrosse, Nicolas University of Glasgow 

Nicolas.Labrosse@glasgow.ac.uk 

Lavassa, Eleni University of Athens 

mygdalo@hotmail.co.uk 

Le Chat, Gaetan Observatoire de Paris 

gaetan.lechat@obspm.fr 

Lee, Ed K.U. Leuven 

edwin.lee@wis.kuleuven.be 

Leenaarts, Jorrit Utrecht University 

j.leenaarts@uu.nl 

Lesovoi, Sergey 

Lugaz, Noe 

Institute of Solar-Terrestrial Physics 

lesovoi@iszf.irk.ru 

University of Hawaii 

nlugaz@ifa.hawaii.edu 

USA 

170 



RUSSIA 

GREECE 


GREECE 

GERMANY 

USA 

RUSSIA 

SCOTLAND 

GREECE 

FRANCE 

BELGIUM 

NETHERLANDS 

RUSSIA 

USA

Mackovjak, Simon Comenius University 

simon.mackovjak@gmail.com 

Madjarska, Maria Armagh Observatory 

madj@arm.ac.uk 

Malandraki, Olga National Observatory of Athens 

omaland@astro.noa.gr 

Mann, Gottfried Leibniz Institut für Astrophysik Potsdam 

GMann@aip.de 

Markova , E. Observatory Upice 

markova@obsupice.cz 

Marsch, Eckart Max Planck Institute for Solar System Research 

marsch@mps.mpg.de 

Martinez Pillet, Valentin Instituto de Astrofisica de Canarias 

vmp@iac.es 

Martinez-Galarce, Dennis Lockheed Martin Solar & Astrophysics Laboratory 

denmart@lmsal.com 

Martinez-Sykora, Juan Lockheed Martin Solar & Astrophysics Laboratory 

juanms@lmsal.com 

Masson, Sophie NASA Goddard Space Flight Center 

sophie.masson@nasa.gov 

Melnikov, Victor Central Astronomical Observatory at Pulkovo of RAS 

melnikov@nirfi.sci‐nnov.ru 

Meshalkina, Nataliia Institute of Solar-Terrestrial Physics 

nata@iszf.irk.ru 

Meszarosova, Hana Astronomical Institute 

hana@asu.cas.cz 

Meyer-Vernet, Nicole Observatoire de Paris, CNRS 

nicole.meyer@obspm.fr 

Miteva, Rositsa Observatoire de Paris 

rositsa.miteva@obspm.fr 

Moravec, Zdenek J. E. Purkyne University 

zdenek.moravec@ujep.cz 

Mordvinov, Alexander Institute of Solar-Terrestrial Physics 

avm@iszf.irk.ru 

Moschou, Sofia Paraskevi University of Athens 

sofia_paraskevi@hotmail.com 

SLOVAKIA 

N. IRELAND 

GREECE 

GERMANY 

171 


GERMANY 

SPAIN 

USA 

USA 

USA 

RUSSIA 

RUSSIA 


FRANCE 

FRANCE 


RUSSIA 

GREECE

Nakariakov, Valery University of Warwick 

V.Nakariakov@warwick.ac.uk 

Nindos, Alexander University of Ioannina 

anindos@cc.uoi.gr 

Olluri, Kosovare University of Oslo 

kosovare.olluri@astro.uio.no 

Olshevskyi, Viacheslav Main Astronomical Observatory 

sya@mao.kiev.ua 

Ontiveros, Veronica University of Ioannina 

vontiver@cc.uoi.gr 

Osswald, Vera Editor Assistant, Living Reviews in Solar Physics 

Vera.Osswald@aei.mpg.de 

Paouris, Evangelos University of Athens 

evpaouris@phys.uoa.gr 

Papailiou, Maria University of Athens 

mpapahl@phys.uoa.gr 

Parenti, Susanna Royal Observatory of Belgium 

s.parenti@oma.be 

Pariat, Etienne Observatoire de Paris 

etienne.pariat@obspm.fr 

Passos , Dario CENTRA-IST 

dariopassos@ist.utl.pt 

Patsou, Ioanna University of Athens 

ipatsou@phys.uoa.gr 

Patsourakos, Spiros University of Ioannina 

spatsour@cc.uoi.gr 

Pesnell, William NASA Goddard Space Flight Center 

William.D.Pesnell@nasa.gov 

Peter, Hardi Max-Planck-Institut für Sonnensystemforschung 

peter@mps.mpg.de 

Podgorny, Igor Institute of Astronomy of RAS 

podgorny@inasan.ru 

Podgorny, Alexander Lebedev Physical Institute of RAS 

podgorny@fian.fiandns.mipt.ru 

Poedts, Stefaan K.U. Leuven 

Stefaan.Poedts@wis.kuleuven.be 

UK 

GREECE 

NORWAY 

UKRAINE 

GREECE 

GERMANY 

GREECE 

GREECE 

BELGIUM 

FRANCE 

PORTUGAL 

GREECE 

GREECE 

USA 

GERMANY 

RUSSIA 

RUSSIA 

BELGIUM 

172

Popova, Helen Moscow State University 

popovaelp@hotmail.com 

Preka-Papadema, Panagiota University of Athens 

ppreka@phys.uoa.gr 

Puzynya, Valery Radiophysical Research Institute 

vale‐r2006@yandex.ru 

Ramelli, Renzo Instituto Ricerche Solari Locarno 

ramelli@irsol.ch 

Rathore, Bhavna University of Oslo 

bhavna.rathore@astro.uio.no 

Reznikova, Veronika National Astronomical Observatory of Japan 

reznik@solar.nro.nao.ac.jp 

Robbrecht, Eva Royal Observatory of Belgium 

Eva.Robbrecht@oma.be 

Rodriguez, Luciano Royal Observatory of Belgium 

rodriguez@oma.be 

Rollett, Tanja University of Graz 

tanja.rollett@uni‐graz.at 

Romano, Paolo Catania Astrophysical Observatory, INAF 

paolo.romano@oact.inaf.it 

Roth, Markus Kiepenheuer-Institut für Sonnenphysik 

mroth@kis.uni‐freiburg.de 

Rouppe van der Voort, Luc University of Oslo 

rouppe@astro.uio.no 

Roussev, Ilia University of Hawaii 

iroussev@ifa.hawaii.edu 

Rubio da Costa, Fatima Max Planck Institute for Solar System Research 

rubio@mps.mpg.de 

Rudawy, Pawel University of Wroclaw 

rudawy@astro.uni.wroc.pl 

Rutten, Robert Utrecht University 

R.J.Rutten@uu.nl 

Sasso, Clementina Osservatorio Astronomico di Capodimonte 

godawa@hotmail.com 

Savcheva, Antonia Boston University 

savcheva@bu.edu 

RUSSIA 

GREECE 

RUSSIA 

SWITZERLAND 

NORWAY 

JAPAN 

BELGIUM 

BELGIUM 

AUSTRIA 

ITALY 

GERMANY 

NORWAY 

USA 

GERMANY 

POLAND 

173 

NETHERLANDS 

ITALY 

USA

Schlichenmaier, Rolf Kiepenheuer-Institut für Sonnenphysik 

schliche@kis.uni‐freiburg.de 

Schmidt, Wolfgang Kiepenheuer-Institut für Sonnenphysik 

wolfgang@kis.uni‐freiburg.de 

Schmieder, Brigitte Observatoire de Paris 

brigitte.schmieder@obspm.fr 

Schulz, Frank Managing Editor, Living Reviews in Solar Physics 

editorlr@aei.mpg.de 

Schwartz, Pavol Astronomical Institute, Academy of Sciences of the 


schwartz@asu.cas.cz 

Sekse, Dan Henrik University of Oslo 

d.h.sekse@astro.uio.no 

Selwa, Malgorzata K.U. Leuven 

mag.selwa@wis.kuleuven.be 

Severino, Giuseppe Osservatorio Astronomico di Capodimonte, INAF 

severino@na.astro.it 

Skala, Jan J. E. Purkinje University in Usti nad Labem 

jskala@physics.ujep.cz 

Skender, Marina University of Zagreb 

marina@irb.hr 

Sobotka, Michal Astronomical Institute, Academy of Sciences of the 


msobotka@asu.cas.cz 

Soler, Roberto K.U. Leuven 

roberto.soler@wis.kuleuven.be 

Spadaro, Daniele Osservatorio Astrofisico di Catania, INAF 

dspadaro@oact.inaf.it 

Spanier, Felix Universität Würzburg 

fspanier@astro.uni‐wuerzburg.de 

Stangalini, Marco Universitá di Roma Tor Vergata 

marco.stangalini@roma2.infn.it 

Steed, Kimberley 

Straus, Thomas 

K.U. Leuven 

kimberley.steed@wis.kuleuven.be 

Osservatorio Astronomico di Capodimonte, INAF 

straus@oacn.inaf.it 

GERMANY 

GERMANY 

FRANCE 

GERMANY 

174 


NORWAY 

BELGIUM 

ITALY 


CROATIA 


BELGIUM 

ITALY 

GERMANY 

ITALY 

BELGIUM 

ITALY

Stupishin, Alexey St.Petersburg State University 

agstup@yandex.ru 

Susino, Roberto Osservatorio Astrofisico di Catania, INAF 

sur@oact.inaf.it 

Sych, Robert Institute of Solar-Terrestrial Physics SB RAS 

sych@iszf.irk.ru 

Syntelis, Petros RCAAM, Academy of Athens 

psyntelis@gmail.com 

Temmer, Manuela University of Graz 

manuela.temmer@uni‐graz.at 

Teriaca, Luca Max-Planck-Institut für Sonnensystemforschung 

teriaca@mps.mpg.de 

Testa, Paola Harvard-Smithsonian Center for Astrophysics 

ptesta@cfa.harvard.edu 

Tokhchukova, Susanna Special Astrophysical Observatory of RAS 

stokh@mail.ru 

Trottet, Gerard Observatoire de Paris 

gerard.trottet@obspm.fr 

Trujillo Bueno, Javier Instituto de Astrofísica de Canarias 

jtb@iac.es 

Tsiropoula, Georgia National Observatory of Athens 

georgia@space.noa.gr 

Tsuneta, Saku National Astronomical Observatory of Japan 

saku.tsuneta@nao.ac.jp 

Tziotziou, Kostas RCAAM, Academy of Athens 

kostas@space.noa.gr 

Utz, Dominik University Graz 

utz@iaa.es 

Van Doorsselaere, Tom K.U. Leuven 

tom.vandoorsselaere@wis.kuleuven.be 

Vandas, Marek 

Vanninathan, Kamalam 

Astronomical Institute, Academy of Sciences of the 


vandas@ig.cas.cz 

Armagh Observatory 

kva@arm.ac.uk 

RUSSIA 

ITALY 

RUSSIA 

GREECE 

AUSTRIA 

GERMANY 

USA 

RUSSIA 

FRANCE 

SPAIN 

GREECE 

JAPAN 

GREECE 

AUSTRIA 

BELGIUM 

175 


UK

Varady, Michal J.E. Purkyne University 

mvarady@physics.ujep.cz 

Verdini, Andrea Royal Observatory of Belgium 

verdini@oma.be 

Veronig, Astrid University of Graz 

astrid.veronig@uni‐graz.at 

Vial, Jean-Claude Université Paris-Sud & CNRS 

jean‐claude.vial@ias.u‐psud.fr 

Vidojevic, Sonja Observatoire de Paris 

sonja.vidojevic@obspm.fr 

Vissers, Gregal University of Oslo 

g.j.m.vissers@astro.uio.no 

Vitas, Nikola SRON Netherlands Institute for Space Research 

n.vitas@sron.nl 

Viticchie, Bartolomeo Research and Scientific Support Department, ESA 

bartolomeo.viticchie@esa.int 

Vourlidas, Angelos Naval Research Laboratory 

vourlidas@nrl.navy.mil 

Warnecke, Jörn Stockholm University 

joern@nordita.org 

Wedemeyer-Böhm, Sven University of Oslo 

svenwe@astro.uio.no 

van Wettum, Tijmen Max-Planck-Institut für Sonnensystemforschung 

vanwettum@mps.mpg.de 

Williams, David University College London 

drw@mssl.ucl.ac.uk 

Zaatri, Amel Centre de Recherche en Astronomie Astrophysique et 

Géophysique 

a.zaatri@craag.dz 

Zacharias, Pia International Space Science Institute 

pia.zacharias@issibern.ch 

Zaqarashvili, Teimuraz 

Zharkova, Valentina 

Space Research Institute, Austrian Academy of Sciences 

teimuraz.zaqarashvili@oeaw.ac.at 

University of Bradford 

v.v.zharkova@brad.ac.uk 

176 


BELGIUM 

AUSTRIA 

FRANCE 

FRANCE 

NORWAY 

NETHERLANDS 

NETHERLANDS 

USA 

SWEDEN 

NORWAY 

GERMANY 

UK 

ALGERIA 

SWITZERLAND 

AUSTRIA 

UK

Zlotnik, Elena Institute of Applied Physics RAS 

zlotnik@inbox.ru 

Zuccarello, Francesca University of Catania 

Francesca.Zuccarello@oact.inaf.it 

Zuccarello, Francesco K.U. Leuven 

francesco.zuccarello@wis.kuleuven.be 

RUSSIA 

ITALY 

BELGIUM 

177

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