Transient Filamentation of a Laser Beam in a Thermal Force Dominated Plasma

Abstract

Experimental evidence for the transient phase of the filamentation instability of a laser beam in a thermal force dominated plasma is presented. When the laser beam is crossed with a weaker degenerate probe beam at a small angle, the interference of the two beams drives a thermally enhanced ion grating which during its transient phase acts to seed the filamentation/forward Brillouin instability.