GIGAWATT X-RAY SOURCE FROM LASER-PLASMA INTERACTION WITH A 50-TW, SUBPICOSECOND LASER

Aluminum x-ray emission near the He-alpha resonance line from high-int ensity (>10(19) W/cm(2)) subpicosecond laser-plasma interaction is pre sented. Obtention of characteristics of x-ray lines is significant of laser-beam interaction with dense matter, as long as the contribution of the laser-pulse pedestal is weak. By studying the evolution of x-ra y spectra versus laser-intensity and laser-pulse shape, we correlate t he laser-intensity contrast ratio, the density-gradient scale length, and the duration of the x-ray pulses. Such a plasma is a bright and sh ort x-ray source. (C) 1997 Optical Society of America.