INCREASED SATURATED LEVELS OF STIMULATED BRILLOUIN-SCATTERING OF A LASER BY SEEDING A PLASMA WITH AN EXTERNAL LIGHT-SOURCE

The reflectivity of laser light due to stimulated Brillouin scattering (SBS) from long-scale plasmas normally saturates when the laser inten sity is increased sufficiently. Nevertheless a significant increase in the SBS reflectivity back into the beam cone results from a subtle ch ange in the target geometry, done for the purpose of seeding SBS. The key element is apparently the injection into the plasma of a modest ex ternal electromagnetic seed at a wavelength near that of the scattered light.