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

摘要

We have conducted experiments to determine the effects of target thickness on the time history and spectra from short pulse laser produced plasmas. A reduced contribution to conduction cooling was achieved by using thin targets. The experiment was done using aluminum foils of thickness ranging from 250 A to 1250 A. The foils were heated with a 400 nm, 150 fs (FWHM), 250 mJ laser focused to a spot size of 2 μm, resulting in a peak intensity of 5.3 × 10~19 W/cm~2. The 1s~2-1s2p transition in He-like aluminum was temporally resolved using a 900 fs x-ray streak camera. An analytic model is derived to describe the time rate of change of the ls2-1s2p transition in He-like aluminum.