Spatiotemporal Evolution of Stimulated Raman Scattering in the Absolute and Convective Regimes¤

A three-wave interaction (3WI) code is developed to study the stimulated Raman scattering (SRS) in both absolute and convective regimes. In the simulations, the time and spatial evolutions of a plasma wave are described by temporal growth rate and spatial factor, respectively. The spatial factors in di?erent phases and di?erent instability regimes are investigated. It is found that the spatial factor is caused by the ˉnite velocity of the pump wave in the ˉrst phase and by damping in the last phase. With inclusion of the spatial factor, the temporal growth rate decreases and the threshold for SRS for a ˉnite frequency mismatch increases. Meanwhile, the e?ects of wave frequency mismatch on the temporal growth rate are also discussed.