STABILITY OF INTENSE LASER PROPAGATION IN AN UNDERDENSE HOLLOW CHANNEL PLASMA

The stability of very intense laser pulses (I less than or similar to 10(18) W/cm(2)) as they propagate through and are guided by a hollow c hannel in an underdense plasma is investigated. It is shown analytical ly and in two-dimensional (2-D) particle-in-cell (PIC) simulations tha t instabilities [Raman forward scatter (RFS)] would completely destroy the beam in homogeneous plasmas or parabolic channel plasmas. However , in hollow channel plasmas these instabilities can be completely supp ressed. The results suggest that hollow plasma channels may be effecti ve in transporting ultra-intense lasers over many Rayleigh lengths. (C ) 1996 American Institute of Physics.