DEPENDENCE OF STIMULATED BRILLOUIN-SCATTERING ON LASER INTENSITY, LASER F-NUMBER, AND ION SPECIES IN HOHLRAUM PLASMAS

Stimulated Brillouin scattering has been studied in plasma conditions approaching those expected within laser-driven cavities (hohlraums) ca pable of driving a fusion capsule to ignition with x rays. These condi tions are achieved using a gas-filled hohlraum design that was fielded at the Nova laser. As the intensity of an interaction beam (351 nm in wavelength) is increased above an onset value I-c, the measured Brill ouin backscatter into the lens rises sharply and saturates. I-c decrea ses as the optic f number increases. The saturation level depends on t he gas ion species.