INTERACTION OF TERAWATT LASER WITH PLASMA

Experimental investigations on interactions of a terawatt laser (0.5-2 .5 TW) with an underdense plasma are reported. Formation of self-chann eling longer than the vacuum Rayleigh length is observed when ultrasho rt (100 fs in FWHM) high power (similar to 2 TW) laser pulses are focu sed into a gas (He, Ar, N-2) filled chamber. In addition to the format ion of self-channeling along the laser axis, a bright radiation in the transverse direction of the channel was observed for the highly excit ed dense gases. This sideway radiation was observed for all three gase s and especially for N-2, sideway jet-like radiation (we call it elect ron sideway-jet) was monitored. The energy of the emitted electrons we re estimated to be similar to 10 keV from the range of electron trajec tories in N-2. (C) 1997 Elsevier Science B.V.