A spectroscopic analysis of near solid density plasmas

Targets of thin (0.1 mu m), Al buried beneath 0.1 mu m plastic overlay have been irradiated by the 350 fs CPA pulse from the 248 nm Titania KrF laser at irradiances: of 10(17)W/cm(2). We report a study of-the radiative proper ties of the Al plasma using X-ray emission spectroscopy. It is demonstrated that short-pulse irradiation of buried-layer targets can produce a plasma with close to solid densities and electron temperatures of several hundred eV. We examine the effect that a long duration (5-50 ns) low intensity (sim ilar to 5 X 10(8) W/cm(2)) prepulse has on the measured values of electron density and temperature. The experimental technique will allow the determin ation of the accuracy of LTE radiative calculations in this new regime of e xtremely high material energy density.