Laser-plasma instabilities in large plasmas irradiated at 1. 06. mu. m and the wavelength scaling of the absorption, hot-electron production, ablation pressure for 1. 06-, 0. 53-, and 0. 35-. mu. m light

Abstract

Plasmas were created by exploding 7000 A thick CH foils at the irradiation conditions: 1.064 ..mu..m, 3 kJ, 2.5 x 10/sup 15/ W/cm/sup 2/, 900 ps FWHM, 400 ..mu..m spot diameter. Ten percent of the laser energy appeared as Raman light and 0.04% as 3..omega../sub 0//2 light. The 3..omega../sub 0//2 light and the 30-70 keV X rays occurred simultaneouly at t=-120/sup +50//sub -//sub 200/ psec and lasted only 300 psec FWHM. The foil was calculated to explode to n/sub c/4 at t=-300 psec. The spectrum and angular distribution of the Raman light were also measured. Time-resolved spectral measurements have been made in experiments with 5320 A laser light in a 600-900 psec FWHM pulse. The scaling of the 3..omega../sub 0//2 light with both the laser spot size and pulse length has been studied