Probing the microscopic state of warm dense matter

We have performed spectrally and angularly resolved x-ray scattering measurements in solid density plasmas produced by shock compression with a high power laser. The experiments have been performed at the VULCAN laser facility and at the LULI2000 facility. We have investigated warm and dense low-Z materials with particular regards to the regime where electron-ion correlation becomes important (i.e., the hydrodynamic regime). In these experiments, we used a secondary plasma to generate an intense source of x-ray radiation that is then scattered across the sample and observed in a forward scattering geometry and dispersed using a graphite Bragg spectrometer. The shock properties have been monitored with a dual color VISAR and streaked optical pyrometry, as well as with a XUV flat-field spectrometer. The inferred properties of the dense plasma from the scattering data are discussed and detailed comparison with statistical models of strongly coupled plasmas is reported.