STUDY OF LASER-HOLE BORING INTO OVERDENSE PLASMAS

Laser channeling into an overdense plasma was studied using time-resol ved spectra of a backscattered laser Light. A 1053 nm laser light was focused on a preformed plasma at a laser intensity of 2 x 10(17) W/cm( 2) with a pulse duration of 100 psec. The preformed plasma was created with a 100-mu m plastic target irradiated by 351-nm laser lights. Tem poral profiles of the backscattered light and the angular distribution of scattered light indicate laser-hole boring in the preformed plasma . The x-ray pinhole images and strong redshift of the backscattered li ght spectrum are consistent with the channel formation into an overden se region.