Brillouin Scattering in Long-Scale-Length Laser Plasmas

LLE Review, Volume 67 119 The experimental study of parametric instabilities in longscale-length laser plasmas is very important for inertial confinement fusion (ICF). Backscattered light near the incident light wavelength has been observed in many laserplasma experiments and is generally attributed to stimulated Brillouin scattering (SBS).1,2 Stimulated Brillouin scattering is a parametric instability in which an incident electromagnetic wave decays into another electromagnetic wave and an ion-acoustic wave.3,4 The instability can grow over a large volume of plasma when ne < ncr, where ne and ncr are the electron and critical densities, respectively. (Here ncr indicates the critical density for 1054-nm laser light.) Stimulated Brillouin scattering in future, long-scale-length ICF plasmas may be significant and could pose problems for efficient coupling of laser light to ICF targets.