SPECTROSCOPY OF COMPRESSED HIGH-ENERGY DENSITY MATTER

A theoretical and experimental time-resolved spectroscopic investigati on of indirectly driven microsphere implosions is described. The plasm a dynamics is studied for several fill gases with a trace amount of ar gon. Through an analysis of the line profile of Ar XVII 1s(2)-1s(3)p P -1, with a line center position at E(v) = 3684 eV, the evolution of th e plasma density and temperature as a function of fill gas is examined . The theoretical calculations are performed with a fast computer code , which has been previously benchmarked through the analysis of specif ic complex ionic spectra in hot dense plasmas. The experimental aspect of the work utilizes the Lawrence Livermore National Laboratory Nova 10 beam laser facility to indirectly drive the implosion of a gas fill ed plastic microsphere contained in a gold Holhraum target. The dynami cal density measurement is derived from a streak camera linewidth meas urement and a comparison with the computed profile. Calculations demon strate that in certain cases there can be a substantial ion dynamics e ffect on the line shape. The frequency fluctuation model is used to co mpute the effect on the line profile and a comparison with the experim ental spectra provides evidence that ion dynamics may be affecting the Line shape. This study provides a method for obtaining an improved un derstanding of the basic processes dominating the underlying plasma ph ysics of matter compressed to a state of high energy density.