PROPAGATION OF INTENSE, ULTRASHORT LASER-PULSES THROUGH PREIONIZED PLASMA SLABS

Relativistic self-focusing and channel formation induced by intense, u ltrashort laser pulses in preionized targets is modeled for accessible experimental parameters. The stability of channel formation is limite d by the nonparaxiality of the laser beam in regions of tight self-foc using. This issue is examined with recently developed nonparaxial theo ry. Channel formation is also characterized in terms of the transmitte d pulse spectrum, the transmitted laser intensity profile, and the rad ial electron density distribution. Calculations indicate a signature s pectral shift in transmission biased toward longer wavelengths, which is attributed to the rapid expulsion of electrons away from the propag ation axis.