Plenarvorträge - DPG-Tagungen

Plasmaphysik Mittwoch
dann in einer Messkammer für Anwendungen zur Verfügung. Ein besonderes
Problem bei Festkörperplasmen ist der Schutz optischer Komponenten
vor Debris. Es werden verschiedene Verfahren zur Debrisreduzierung,
u.a. die Anwendung von Kapillarfiltern und -optiken erprobt und
die Eigenschaften der Plasmaquelle beschrieben.
[1] BMWA-Verbundprojekt SpeXUV, Förderkennzeichen 16IN0211
P 17.23 Mi 17:45 Foyer
Electrical Resistivity of High Energy Density Matter Generated
by Intense Heavy Ion Beams — •Serban Udrea 1 , Naeem
Tahir 2 , Dmitry Varentsov 1 , Carmen Constantin 3 , Eduard
Dewald 3 , Joachim Jacoby 4 , and Dieter H.H. Hoffmann 1,2 —
1 Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstr.
9, 64289 Darmstadt — 2 Gesellschft für Schwerionenforschung,
Planckstr. 1, 64291 Darmstadt — 3 Lawrence Livermore National Laboratory,
7000 East Ave., Livermore, CA 94550-9234, USA — 4 Institut
für Angewandte Physik, Universität Frankfurt, Robert-Mayer-Str. 2-4,
60325 Frankfurt am Main
Intense heavy ion beams are an excellent tool to produce large volumes
of high energy density (HED) matter. The thermodynamic and transport
properties of such systems are of interest for fundamental as well as for
applied research. In this work we present measurements of the electrical
resistivity of metallic wires heated by intense heavy ion beams. The
targets (10 mm long, 0.25 mm diameter) were made of lead, copper and
silver. Oxygen and argon 1 µs long ion beam pulses with intensities up
to 6 ·10 10 particles and energies of 200 and 300AMeV, respectivelly have
been used as drivers. The high energy densities deposited in the targets
(up to 1 kJ/g) have been achieved by focussing the ion beams with a
high current plasma lens down to a diameter of 0.7 − 1.0 mm FWHM.
The measurements are compared with results obtained by 2D simulations
of the hydrodynamic response of the target material and the electrical
current flow calculations.
P 17.24 Mi 17:45 Foyer
Experimental Results on the Energy Loss of Carbon Ions in
Dense, Laser-Produced Plasmas — •Muhammad Youssef 1 ,
Abel Blazevic 1 , Erik Brambrink 1 , Pascal Pirzadeh 1 , Gabriel
Schaumann 1 , Matthias Geißel 1 , Markus Roth 1 , and Dieter
H.H. Hoffmann 1,2 — 1 Institut für Kernphysik, Technische Universität
Darmstadt, Schlossgartenstr. 9, 64289 Darmstadt — 2 Gesellschft für
Schwerionenforschung, Planckstr. 1, 64291 Darmstadt
One of the main research interests of the plasma physics group at
the Gesellschaft für Schwerionenforschung Darmstadt is the investigation
of the energy loss of swift heavy ions in dense plasmas. In this work
we present experimental results on the energy loss of 12 C +6 ions with a
4.8MeV/u initial energy in dense, laser-produced plasmas. These plasmas
were generated using the nhelix laser system (120 J, 15 ns, λ = 1064 nm)
by irradiating teflon foils of 2.70−4.05µm. The energy loss of the carbon
projectiles was measured using the time-of-flight method.
P 17.25 Mi 17:45 Foyer
Space Resolved X-Ray Spectroscopy in Long Pulsed Laser Plasmas
— •G. Rodríguez Prieto 1 , M.S. Schollmeier 1 , F.B. Rosmej
2 , A. Azima 3 , A. Blazevic 1 , E. Brambrink 1 , P. Pirzadeh 1 ,
O.N. Rosmej 1 , G. Schaumann 1 , and D.H.H. Hoffmann 1 — 1 GSI
Planckstrasse 1, 64291 Darmstadt — 2 PILMA, Université de Provence
et CNRS, Marseille, France — 3 Universität Heidelberg, Germany
In this work we present our preliminary results of spectroscopic investigations
of plasmas produced by the NHELIX laser facility (140 Joules
in 14 ns, λ = 1.064 nm.) at GSI, Darmstadt. The measurements have
employed two mica spectrometers with a resolution λ/∆λ of 3000 at
wavelengths less than 2 nm. Spectrographic data were used to achieve
space resolved information about the ion velocity distribution, electron
density and electron temperature inside the plasma.
P 17.26 Mi 17:45 Foyer
Design and extension of a Nd-YAG/glass lasersystem —
•Armin Azima 1 , A. Blaszevic 2 , E. Brambrink 2 , P. Neumayer
2 , P. Pirzadeh 2 , G. Schaumann 2 , M. Schollmeier 2 , G.
Rodríguez 2 , J. Kluge 1 , M. Roth 2 , and D.H.H. Hoffmann 2 —
1 Universitát Heidelberg — 2 GSI Darmstadt Plasmaphysik
The propose of this work is to link the beam of a Nd-YAG oscillator
into the NHELIX amplifier chain, which consists of several Nd-Glass amplifier
rods and to focus the amplified light on a target, for analyzing
plasmas with the so called ” backlighter“ imaging method. The special
feature of the system will be the use of two laserpulses simultaneosly
in the same amplifier chain. One beam from a new oscillator and the
other one from an already in use oscillator, which are having different
pulse length (15ns and 500ps FWHM). Although they are propagating
parallel and simultaneosly along the same amplifier rods, they will be
spatially divided after amplification. This is realized due to controlling
the polarization and using some polarizers as kind of a light duplexer.
The estimated light intensity of the two beams in the focus point will be
10 1 3 W/(cm 2 ) and 10 1 4 W/(cm 2 ).
The beam propagation was simulated with the MIRO-Code, too.
P 17.27 Mi 17:45 Foyer
Energy and emission distributions of ions in laser ablated plasmas
from binary TiAl targets — •S. N. Srivastava and K. P.
Rohr — Fachbereich Physik, Universität Kaiserslautern, Germany
The present work for the first time compares spectra of ion energy distributions
in laser produced particle beams from pure metals with a series
of its composite materials. Targets are Al and Ti and Ti25Al75, Ti34Al66,
Ti50Al50 and Ti75Al25, respectively. The measurements are resolved for
the different ion groups. The plasma was produced by obliquely incident
Q-switched laser pulses (EL = 130 mJ, t = 5 ns and l = 1.06 mm) focused
to an ablation area of about 0.3 mm2. Most apparent findings are:
1. The averaged particle energies increase with the charge and the atomic
mass of the ions. This holds for all emission angles and for both pure and
binary targets. 2. As a function of the ionic charge the angular emission
cone steepens and moves towards the direction of the incoming laser
beam. 3. The absolute values of the averaged energies of corresponding
species in the monoatomic and complex beam are essentially equal.
P 17.28 Mi 17:45 Foyer
Segregation of neutrals and ions in laser ablated plasmas from
binary TiAl targets — •S. N. Srivastava and K. P. Rohr — Fachbereich
Physik, Universität Kaiserslautern, Germany
Till now, systematic and differential experiments of laser ablated particle
pulses exists only for mono-atomic target systems.The present experiment
for the first time compares in detail angular emission characteristics
of laser produced plasma pulses ablated from binary material of variable
stoichiometry with each other and with those of its pure components.
As an example system we have chosen Titanium-Aluminium compounds
(TiAl). The plasma was produced by obliquely incident Q-switched laser
pulses (EL = 130 mJ, t = 5 ns and l = 1.06 mm) focused to an ablation
area of 0.3 mm2. The most remarkable results are: 1. All emission
distributions can be well fitted by Gauß-function. 2. The widths of the
emission cones of both, ions and total number of particles, steepens as
a function of the average atomic mass A and can be well approximated
by G = k/A + c. Hereby k systematically depends on the size of the
focal area. 3. The width is decreasing with increasing charge state. 4.
The direction of the emission turns towards the direction of the incoming
laser beam as a function of the particles charge state. The results are
of practical interest and give useful datasets for theoretical simulations.
P 17.29 Mi 17:45 Foyer
Design and extension of a Nd-YAG/glass lasersystem —
•Armin Azima 1 , A. Blaszevic 2 , E. Brambrink 2 , P. Neumayer
2 , P. Pirzadeh 2 , G. Schaumann 2 , M. Schollmeier 2 , G.
Rodríguez 2 , J. Kluge 1 , M. Roth 2 , and D.H.H. Hoffmann 2 —
1 Universitát Heidelberg — 2 GSI Darmstadt Plasmaphysik
The propose of this work is to link the beam of a Nd-YAG oscillator
into the NHELIX amplifier chain, which consists of several Nd-Glass amplifier
rods and to focus the amplified light on a target, for analyzing
plasmas with the so called ” backlighter“ imaging method. The special
feature of the system will be the use of two laserpulses simultaneosly
in the same amplifier chain. One beam from a new oscillator and the
other one from an already in use oscillator, which are having different
pulse length (15ns and 500ps FWHM). Although they are propagating
parallel and simultaneosly along the same amplifier rods, they will be
spatially divided after amplification. This is realized due to controlling
the polarization and using some polarizers as kind of a light duplexer.
The estimated light intensity of the two beams in the focus point will be
10 1 3 W/(cm 2 ) and 10 1 4 W/(cm 2 ).
The beam propagation was simulated with the MIRO-Code, too.