Reflectivity of stimulated Brillouin scattering in picosecond time scales

Abstract

Measurements of reflectivity of stimulated Brillouin scattering, from an underdense, homogeneous plasma, irradiated by a 10 ps-1.06&mu;m laser pulse, show an increase from 10^-4 to 10^-2, as the laser intensity is varied between 10¹³ to 10¹⁵ W/cm². Numerical simulations have been developed to interpret these data. At low laser intensity, (<10¹⁴ W/cm²), the low reflectivity is well explained as being due to saturation of the instability in the convective regime, and good agreement with numerical simulations has been obtained. At high laser intensity, the model predicts higher reflectivities than measured in the experiment, although non-linear effects in ion sound waves evolution have been observed.