FILAMENTATION AND STIMULATED BRILLOUIN-SCATTERING IN A TURBULENT-PLASMA

This paper presents a theory of filamentation and stimulated Brillouin scattering (SBS) of high-frequency electromagnetic radiation in a wea kly collisional plasma with ion-acoustic turbulence. When the square o f the wavelength of the plasma perturbations is less than the product of the two mean free path lengths of an electron with respect to its c ollisions with turbulent fluctuations and with electrons, the influenc e of cold highly collisional electrons on the parametric instabilities becomes apparent. It is shown that the plasma turbulence lowers the f ilamentation threshold, and the SBS threshold can be either lowered or raised. The dependence of the SBS and filamentation thresholds on the electron mean free path length in the turbulent plasma and on the ani sotropy of the plasma turbulence is determined. The corresponding depe ndence of the spatial scale of the most efficiently growing filaments and their spatial growth rate are found. (C) 1998 American Institute o f Physics.