Measuring Ionization in Highly Compressed, Near-Degenerate Plasmas
ORAL
Abstract
A precise knowledge of ionization at given temperature and density is required to accurately model compressibility and heat capacity of materials at extreme conditions. We use x-ray Thomson scattering to characterize the plasma conditions in plastic and beryllium capsules near stagnation in implosion experiments at the National Ignition Facility. We expect the capsules to be compressed to more than 20x and electron densities approaching 10$^{25}$ cm$^{-3}$, corresponding to a Fermi energy of 170 eV. Zinc He$_{\alpha}$ x-rays (9 keV) scattering at 120$^{\circ}$ off the plasma yields high sensitivity to K-shell ionization, while at the same time constraining density and temperature. We will discuss recent results in the context of ionization potential depression at these extreme conditions.
*This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
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