High-Energy Electron Production by the Raman and2ωpeInstabilities in a 1.064-μm-Laser-Produced Underdense Plasma

Experiments on an underdense plasma irradiated with high-intensity 1.064-..mu..m laser light have demonstrated that instabilities operating near (1/4) the critical electron density can produce high-energy electrons. Experimental conditions were as follows: 7000-A CH foil targets, 2.5 x 10/sup 15/ W/cm/sup 2/, 900 psec, 400-..mu..m spot diameter. The 3..omega../sub 0//2 light and 40-keV x rays occurred simultaneously at t = -120 psec (laser peak at t = 0) and lasted only 300 psec full width at half maximum. Ten percent of the laser energy appeared as Raman light and 0.04% as 3..omega../sub 0//2 light.