Measurement of absolute growth rates and saturation phenomena for stimulated Brillouin scattering in aCO2-laser–irradiated plasma

Growth rates and saturation of stimulated Brillouin scattering in a ${\mathrm{CO}}_2$-laser–irradiated plasma are investigated by picosecond Thomson scattering of ruby laser light and backscatter spectroscopy. The temporal growth rates are found to be consistent with theoretical predictions. The ion acoustic waves saturate at a fluctuation amplitude of <20% and subsequently show a modulated temporal behavior, as well as sidebands in the backscatter spectra consistent with saturation by strong ion trapping.