Plenarvorträge - DPG-Tagungen

Extraterrestrische Physik Montag
from shifted Max wellians are developing in the heliospheric interface
region both for protons and H-atoms. For the interpretation of innerheliospheric
measurements this has to be taken into account.
EP 8.5 Mo 17:45 Foyer
Constraints on the Heliospheric Magnetic Field Variation during
the Maunder Minimum from Cosmic Ray Modulation Modelling
— •Klaus Scherer 1 and Horst Fichtner 2 — 1 Institut für
Astrophysik und Extraterrestrische Forschung der Universität Bonn, Auf
dem Hügel 71, 53121 Bonn — 2 Institut für Theoretische Physik IV:
Weltraum- und Astrophysik, Ruhr-Universität Bochum, 44780 Bochum
Using a dynamic multifluid model of the global heliosphere (Bonn
model) we found, that the variation of the heliospheric interface and
the corresponding cosmic ray modulation can not be made responsible
for the increase of the mean cosmic ray flux during the Maunder Minimum.
This is because the diffusion coefficients of cosmic rays required
to simulate their flux increase need an “intrinsic” time variation, i.e. one
that can be attributed to the solar or heliospheric magnetic field, thus, to
the solar dynamo. Our study of the diffusion coefficients constrains the
decrease in the strength of the solar magnetic field during the Maunder
Minimum to about a factor of 4.
EP 8.6 Mo 17:45 Foyer
Ulysses COSPIN/KET observations of Jovian electrons in
the 3-dimensional heliosphere — •H. Kunow 1 , B. Heber 2 ,
R. Müller-Mellin 1 , G. Wibberenz 1 , H. Fichtner 3 , S. E. S.
Ferreira 4 , and M. S. Potgieter 4 — 1 IEAP CAU Kiel, 24118
Kiel, Germany — 2 FB Physik, Universität Osnabrück, Germany —
3 TP4, Ruhr-Universität Bochum, Bochum, Germany — 4 Unit for Space
Physics, Potchefstroom University, Potchefstroom, South Africa
One of the fundamental problems in modern astrophysics is the propagation
of cosmic rays in turbulent magnetic fields, which can be studied
by way of in-situ measurements of energetic particles in the heliosphere.
Measurements of 3-20 MeV electrons from 1990 to 2004 have been made
in the inner three-dimensional heliosphere by the Kiel Electron Telescope
(KET) onboard the Ulysses spacecraft. The Ulysses trajectory provides a
unique opportunity to study the propagation of these electrons in a wide
range of heliographic latitudes and during varying conditions. In order
to interpret these measurements, it is necessary to know their origin and
investigate their propagation, by using sophisticated particle propagation
models. Between 1 and 10 AU Jovian, solar and galactic particles contribute
to the few-MeV electron intensities. In this presentation we will
emphasize on the recent Ulysses KET results. At solar maximum Jovian
electrons could unambiguously be identified from heliographic latitudes
beyond 40 ◦ N and ∼10 AU from the planet, implying an efficient (latitude)
transport of these particles.
EP 8.7 Mo 17:45 Foyer
Properties of high heliolatitude solar energetic particle events:
Ulysses observations — •B. Heber 1 , A. Struminsky 2 , M.-B.
Kallenrode 1 , R. Müller-Mellin 3 , A. Klassen 3 , H. Kunow 3 ,
and A. Posner 4 — 1 FB Physik, Universität Osnabrück, Germany —
2 IZMIRAN, 142190 Troitsk, Moscow region, Russia — 3 IEAP CAU Kiel,
24118 Kiel, Germany — 4 SWRI, San Antonio, TX, USA
We analyze 10 large solar energetic particle events detected by the
Ulysses spacecraft at high heliolatitudes during the recent solar maximum
polar passes. The time intensity profiles from the Ulysses KET
instrument are compared with those measured by SOHO/COSTEP and
GOES near Earth. Surprisingly, the intensity of 50 ◦ , while the corresponding
intensity at Earth varies by several orders of magnitude. We find no correlation
of the Ulysses peak intensities and fluences with respect to the
flare location for the first two days. This implies: 1) nearly isotropic injection
to high heliolatitudes, and 2) similar propagation mechanismen
during the first two days of the event. We find that cross-field particle
transport but not the presence of a shock establishes near equal intensities
at Ulysses and in the ecliptic during the decay phase.
EP 8.8 Mo 17:45 Foyer
Evolution of the galactic cosmic ray electron to proton ratio:
Ulysses COSPIN/KET observations. — •R. Müller-Mellin 1 ,
B. Heber 2 , H. Kunow 1 , G. Wibberenz 1 , S. E. S. Ferreira 3 , and
M. S. Potgieter 3 for the KETPOTCH collaboration — 1 IEAP CAU
Kiel, 24118 Kiel, Germany — 2 FB Physik, Universität Osnabrück, Germany
— 3 Unit for Space Physics, Potchefstroom University, Potchefstroom,
South Africa
The on-going Ulysses mission provides a unique opportunity to study
the propagation and modulation of galactic cosmic rays (GCRs) in detail
in the three-dimensional heliosphere. The intensity of GCRs is modulated
as they traverse the turbulent magnetic field embedded in the solar
wind. These particles are scattered by irregularities in the interplanetary
magnetic field and undergo convection and adiabatic deceleration
in the expanding solar wind. The large-scale heliospheric magnetic field
leads to drifts of GCRs in the interplanetary medium. The time history
of electrons and protons is a suitable tool to investigate the importance
of drifts in heliospheric modulation. In late 2000, the electron to proton
ratio at rigidities of 1.2 GV and 2.5 GV was roughly the same as in the
previous solar maximum, when the solar magnetic field reversed from an
A < 0 to an A > 0-solar magnetic epoch, indicating that drifts are only
of minor importance at solar maximum. After late 2001 the ratio began
to increase again, leading to the conclusion that drifts are becoming increasingly
important again. We will discuss the Ulysses observations and
compare them with the IMP and ICE measurements in the 1980s, which
reveals a similar time profile.
EP 8.9 Mo 17:45 Foyer
X17/4B solar flare on 28 October 2003 — •A. Klassen 1 , H.
Kunow 1 , R. Müller-Mellin 1 , R. Wimmer-Schweingruber 1 ,
and G. Mann 2 — 1 IEAP CAU Kiel, 24118 Kiel, Germany —
2 Astrophysikalisches Institut Potsdam, 14482 Potsdam, Germany
The solar origin and release of near relativistic protons and electrons
during the X17/4B flare measured by the COSTEP/EPHIN experiment
on board the SOHO spacecraft is investigated. These measurements are
combined with ground and space based spectral radio data obtained by
the Tremsdorf spectrograph and the Waves/Wind instrument. Additionally
we use observations of the Ground Level Event (GLE) measured by
neutron monitors. We study the timing of the different phenomena occurring
during the flare in the solar corona with respect to the proton
and electron events measured near and on the Earth. Interpretation of
these results is discussed.
EP 8.10 Mo 17:45 Foyer
STRATIGRAPHY AND AGES OF VOLCANIC DOMES
IN THE HANSTEEN AND HELMET REGIONS ON THE
MOON — •Roland Wagner 1 , James W. Head III 2 , Ursula
Wolf 1 , and Gerhard Neukum 3 — 1 Institute of Planetary Research,
German Aerospace Center (DLR), Rutherfordstrasse 2, D-12489 Berlin,
Germany — 2 Dept. of Geol. Sciences, Brown Univ., Providence, RI,
USA — 3 Institut für Geowissenschaften, Freie Universität Berlin,
Malteserstrasse 74, D-12249 Berlin, Germany
The dominating volcanic process on the moon was the emplacement of
basaltic lava which formed the dark mare regions on the nearside. A spatially
less abundant volcanic process is associated with volcanic domes
formed by lava materials of higher silica content and much higher viscosity,
which are characterized by a high albedo, a strong absorption in the
UV (red spots), and also by a wide range of morphologies. (1) Photogeologic
mapping, (2) measuring crater frequencies on mapped units, and
(3) the application of an impact chronology model was used to put constraints
on the crustal evolution during lunar geologic history. Two areas
displaying volcanic domes were selected for this study: regions Hansteen
(≈ 11.5 o S, 50 o W), and Helmet ((≈ 16 o S, 30 o W). Photogeologic mapping
and measurements of crater frequencies were carried out on Lunar
Orbiter high-resolution frames. Results show that high-silica, highviscosity
volcanism was active during a period of about 3.8-3.9 Gyr and
was comparably short-lived while low-silica, low-viscosity mare basalts
were emplaced during a much more extended period of time (several 100
Myr).
EP 8.11 Mo 17:45 Foyer
Kaliumdichte und leuchtende Nachtwolken über Spitzbergen
und Kühlungsborn — •J. Lautenbach, J. Höffner und C.
Fricke-Begemann — IAP Kühlungsborn
Täglich dringen ca. 110 Tonnen kosmischen Materials in die Erdatmosphäre
ein. Diese extraterrestrischen Teilchen verglühen in der oberen
Atmosphäre, wobei auch Metalle wie z.B. Kalium freigesetzt werden.
Durch chemische Reaktionen in der Erdatmosphäre bilden sich permanente
Metallschichten zwischen 80 und 105 km aus. Leuchtende Nachtwolken
(NLCs) sind dünne Eiswolken die in ca. 84 km durch sehr kalte
Temperaturen gebildet werden. Sie werden schon seit über 100 Jahren in
polaren Breiten und ausschließlich im Sommer beobachtet.
Mit bodengebundenen Lidar-Geräten (light detection and ranging)
können vertikale Rückstreuprofile aufgenommen werden. Daraus lassen