Nonlinear Propagation of Laser Beams near the Critical-Density Surface in the Plasmas of Direct-Drive Targets

LLE Review, Volume 95 179 Introduction The interaction of laser beams with plasmas near the criticaldensity surface is an important characteristic feature of directdrive inertial confinement fusion (ICF) experiments.1,2 One of the main laser–plasma interaction processes is stimulated Brillouin scattering (SBS), which involves the decay of an incident light wave into a scattered light wave and an ionacoustic wave. The process of forward SBS accompanies the filamentation of laser beams and can change the spatial and temporal coherence of laser light propagating into the target.3,4 The process of backward SBS5 is important because it can potentially deplete the laser-beam power delivered to the target. The spectrum of SBS-backscattered light is also useful as a diagnostic of plasma conditions.