Abstract

The first direct experimental investigation on soft x-ray driven ablation has been made with indirect laser illumination geometry using an assembly of a spherical pellet and laser-produced external radiation sources and the time-resolved x-ray backlighting diagnostic method as shown in Fig. 1. Four laser beams of 0.53 /xm from the frequency-doubled Gekko-IV system irradiated the inner surface of Au- or CH-coated concave steel plates with the intensity of 1.0-6.0 X 10^MW/cm² in 100-psecFWHMaf an incident angle of 54°. Two beams were made into a pair so that they irradiated the same spot to generate an intense soft x-ray emission from the Au surface. The plasma characteristics of the Au x-ray emitters were separately diagnosed by filtered soft x-ray diodes which have aluminum photocathodes, x-ray calorimeters, an x-ray transmission grating spectrometer, charge collectors, and a synchronized 40-psec visible probe beam. From comprehensive data analysis of all diagnostics used, it can be concluded that the pellet has been driven by x-ray radiation in case of the Au emitter and by plasma particles in case of CH emitter.

© 1983 Optical Society of America