Solitary waves in a plasma interacting with two counter-propagating laser pulses

Summary form only given, as follows. In this study, we investigate the formation of electromagnetic solitary waves induced by a three-wave interaction among a plasma wave and two counter-propagating laser pulses. The three waves satisfy the matching condition of Raman scattering, /spl omega//sub 0/-/spl omega//sub 1/=/spl omega//sub p/, where /spl omega//sub 0/ and /spl omega//sub 1/ are the frequencies of the pump and the seed pulses respectively, and /spl omega//sub p/ is the electron plasma frequency. The nonlinear interaction was simulated with a one-dimensional fluid model and a particle-in-cell code. The quasi-static fluid model solves eikonal envelope equations, and the particle-in-cell simulation traces the relativistic motion of plasma particles interacting with electromagnetic waves. When the pump intensity is small, there happens regular laser pulse amplification. However, as the pump intensity increases, solitary waves begin to occur and the propagation speed depends on the pump amplitude. As the pump intensity increases, the propagation speed becomes slower. With a larger pump intensity, stochastic patterns are formed in the transmitted pump wave and the plasma wave. In addition, it was observed that the soliton-like waves can be generated at a relatively low laser intensity when two colliding laser pulses are used rather than a single pulse.