Hohlraum energetics with smoothed laser beams

Measurements of radiation temperatures from empty and gas-filled hohlraums heated at the Nova Laser Facility [E. M. Campbell , Laser Part. Beams 9, 20 9 (1991)] show efficient coupling of the laser power to the target when app lying laser beam smoothing techniques. Scattering losses are reduced to the 3% level while the radiation temperatures increased by similar to 15 eV fo r smoothed laser beams. The experimental findings and supporting calculatio ns indicate that filamentation and gain for stimulated Raman and Brillouin scattering is suppressed in the hohlraum plasma for smoothed laser beams. T he scaling of the radiation temperature is well described by integrated rad iation hydrodynamic LASNEX modeling [G. B. Zimmerman and W. L. Kruer, Comme nts Plasma Phys. Controlled Fusion 2, 85 (1975)] following the Marshak scal ing. Peak radiation temperatures are in excess of 230 eV in gas-filled hohl raums in agreement with the detailed LASNEX modeling. (C) 2000 American Ins titute of Physics. [S1070-664X(00)03505-9].