REDUCED CONDUCTION COOLING IN HIGH ENERGY-DENSITY PLASMAS USING ULTRASHORT-PULSE LASER-HEATED THIN FOIL TARGETS

We have conducted experiments to determine the effects of target thick ness on the time history and spectra from short pulse laser produced p lasmas. A reduced contribution to conduction cooling was achieved by u sing thin targets. The experiment was done using aluminum foils of thi ckness ranging from 250 Angstrom to 1250 Angstrom. The foils were heat ed with a 400 nm, 150 fs (FWHM), 250 mJ laser focused to a spot size o f 2 mu m, resulting in a peak intensity of 5.3 x 10(19) W/cm(2). The 1 s(2)-1s2p transition in He-like aluminum was temporally resolved using a 900 fs x-ray streak camera. An analytic model is derived to describ e the time rate of change of the 1s(2)-1s2p transition in He-like alum inum. (C) 1997 Published by Elsevier Science Ltd. All rights reserved.