Plasma simulation studies of stimulated scattering processes in laser-irradiated plasmas

Abstract

The behavior of stimulated Brillouin and Raman scattering is studied by a number of periodic and aperiodic plasma simulations. The one‐dimensional studies at low power, roughly defined by the oscillating velocity of an electron being less than its thermal velocity, tend to support the spatial theory. Typically, in the aperiodic simulations trapping nonlinearities of the electrostatic wave and electron heating can saturate the amount of backscatter at a reasonable level. At high powers in both periodic and aperiodic simulations an x‐type breaking or wave collapse phenomenon occurs after saturation which leads to an equilibration between pondermotive force, electron pressure, and ion pressure. Simulations of a random frequency modulated laser are discussed. Two‐dimensional simulations and their relationship to the one‐dimensional results are briefly mentioned.