Simulation of Stimulated Raman Scattering from Gas-filled Hohlraums

A series of experiments performed at Omega Laser Facility have measured the stimulated Raman and Brillouin backscatter and beam spray of 351nm laser light from gas-filled hohlraums at electron densities from .06 N$_{c}$ to 0.13 N$_{c}$ and electron temperature about 3 keV. Experiments with similar plasma conditions were reported recently (Froula \textit{et al.,} Phys. Plasmas\textbf{, 14}, 055705, 2007 and Meezan, \textit{et al. ibid}, 056304). The experiments were designed to have convective gains for SRS between 5 and 30. The gain was varied with the laser intensity and the fill density. Above .09 N$_{c}$ the simulated and measured backscatter is predominately SRS. PF3D simulations will be presented that compute the effects of SSD and polarization smoothing on the onset intensity for significant reflectivity (R $>$ 1{\%}) as well as the intensity and density scaling of the scatter. The simulated and measured reflectivity and beam spray will be compared. .