ON SELF-FOCUSING OF LASER BEAMS IN PLASMA.

Self-focusing of laser beams in plasma is studied analytically using the thermal (collision produced) and ponderomotive (nonlinear force produced) effects based on the model of Zakharov with solutions of the nonlinear Schroedinger equation. A basic difference appears if the electric field amplitude E is less than the threshold E//t//h (at which the electrodynamic energy density is equal to the gasdynamic pressure) from the contrary case, E less than equivalent to E//t//h. The length of the filamentation process is evaluated and results in large values for E below E//t//h.