A longitudinal electrostatic electron plasma wave excited at the difference frequency of two laser beams is shown to be unstable against filamentation instability in a hot collisionless plasma. The relativistic Vlasov equation has been solved to obtain the nonlinear response of electrons. It is noticed that for a considerable power density of the excited electron plasma wave the growth rate of the filamentation instability is quite high.

• Received 5 November 1984

DOI:https://doi.org/10.1103/PhysRevA.31.4005