Laser scattering in large-scale-length plasmas relevant to National Ignition Facility hohlraums

We have used homogeneous plasmas of high density (up to 1.3 X 10{sup 21} electrons per cm{sup 3}) and temperature ({approximately} 3 keV) with large density scale lengths ({approximately}2 mm) to approximate conditions within National Ignition Facility (NIF) hohlraums. Within these plasmas we have studied the dependence of stimulated Raman (SRS) and Brillouin (SBS) scattering on beam smoothing and plasma conditions at the relevant laser intensity (3{omega}, 2 X 10{sup 15}Wcm{sup 2}). Both SBS and SRS are reduced by the use of smoothing by spectral dispersion (SSD).