Kiel 2004 – wissenschaftliches Programm

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PV: Plenarvorträge

PV IX

PV IX: Plenarvortrag

Donnerstag, 11. März 2004, 08:30–09:15, H\"orsaal G

Compton scattering in warm dense matter — •Siegfried Glenzer — Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 94551, USA

We have recently succeeded measuring the temperature and ionization balance of a previously unexplored regime of high-density matter with a proof-of-principal experiment at the Omega laser facility. We used spectrally resolved 4.75-keV x-ray scattering from solid-density beryllium and carbon plasmas. In our experiments, we observe the Compton-downshifted spectral line that is broadened by the thermal motion of the electrons in the plasma indicating temperatures of up to T_e = 50 eV at densities of 3 × 10²³cm⁻³. We compare our results with calculations of the ionization balance and find that the experimental data test models of electronic properties at high density. These results also suggest that the full range of dense plasmas, from Fermi degenerate, to strongly coupled, to high temperature ideal gas plasmas will now be accessible. For example, as the temperature is increased, the electron velocity distribution as measured by inelastic scattering transitions from a density-dependent parabolic Fermi distribution to the traditional Gaussian Boltzmann distribution. The technique has wide applications, ranging from studying the adiabat and compression of ICF fuels, to temperature measurements for radiatively heated foams. In addition, by accessing the collective scattering regime, basic dense plasma wave physics can be studied.

This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.