Coherent forward stimulated-brillouin scattering of a spatially incoherent laser beam in a plasma and its effect on beam spray.
A statistical model for forward stimulated-Brillouin scattering is developed for a spatially incoherent, monochromatic, laser beam propagating in a plasma. The threshold above which the laser beam spatial incoherence cannot prevent the coherent growth of forward stimulated-Brillouin scattering is computed. It is found to be well below the threshold for self-focusing. Three-dimensional simulations confirm its existence and reveal the onset of beam spray above it. From these results, we propose a new figure of merit for the control of propagation through a plasma of a spatially incoherent laser beam.
Grech
M
M
Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany. mickael.grech@gmail.com
Riazuelo
G
G
Pesme
D
D
Weber
S
S
Tikhonchuk
V T
VT