Interpretation of stimulated Brillouin scattering measurements based on the use of random phase plates
Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, Centre National de la Recherche Scientifique, 91128 Palaiseau cedex, France
2 P. N. Lebedev Physics Institute, Russian Academy of Science, Moscow 117924, Russia
Accepted: 25 February 1997
Experimental reflectivities due to stimulated Brillouin scattering (SBS) and ion acoustic fluctuations have been successfully modelled, over four orders of magnitude of SBS reflectivity, using a newly developed theory of parametric instabilities in randomized laser beams. The observed temporal evolution of SBS has been interpreted using the hydrodynamic evolution of the plasma parameters. Location of SBS in the front part of the plasma is due partly to pump depletion in the SBS-active speckles, and partly to plasma conditions.
PACS: 52.35.Fp – Electrostatic waves and oscillations (e.g., ion-acoustic waves) / 52.35.Mw – Nonlinear waves and nonlinear wave propagation (including parametric effects, mode coupling, ponderomotive effects, etc.) / 52.40.Nk – Laser-plasma interactions (e.g., anomalous absorption, backscattering, magnetic field generation, fast particle generation)
© EDP Sciences, 1997