Absorption of bounds states in hot, dense matter

Preliminary experiments using a long pulse laser generated X-ray source to back-light a short pulse laser heated thin foil have been performed at the Laboratoire pour l'Utilisation des Lasers Intenses (LULI) at Ecole Polytechnique in France. In these experiment, a 2 J, 300 ps, 532 nm laser was used to create the X-ray back-lighter. The primary diagnostic was a von Hamòs spectrograph coupled to a 500 fs X-ray streak camera (TREX-VHS) developed at LLNL. This diagnostic combines high collection efficiency (≈ 10^-4 sr) with fast temporal response (≈ 500 fs), allowing resolution of extremely transient spectral variations. The TREX-VHS was used to determine the time history, intensity, and spectral content of the back-lighter. The second diagnostic, Fourier domain interferometry, provides information about the position of the critical density of the target and thus the expansion hydrodynamics, laying the ground work for the plasma characterization. The plasmas were determined to be moderately to strongly coupled, resulting in absorption measurements that provide insight into bound states under such conditions.