Two-dimensional studies of stimulated Brillouin scattering, filamentation, and self-focusing instabilities of laser light in plasmas

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860845· OSTI ID:6022024

Amin, M R; Capjack, C E ^[1]; Frycz, P; Rozmus, W; Tikhonchuk, V T ^[2]

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1. Department of Electrical Engineering, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada)
2. Department of Physics, University of Alberta, Edmonton, Alberta T6G 2J1 (Canada)

The parametric interaction of an intense laser beam with ion plasma modes in a two-dimensional Cartesian geometry has been studied for the first time by avoiding the paraxial optics approximation. This model allows investigation of the competition between forward, sideward, and backward stimulated Brillouin scattering (SBS) along with filamentation and self-focusing instabilities. It is shown that the SBS saturation level, the angular distribution of transmitted and scattered light, and their temporal dependence are governed mainly by two control parameters: the backward SBS gain coefficient [ital G], and the ratio [alpha][sub [ital s][sub [ital f]]] of the incident beam power to its critical value for the onset of self-focusing. In the case of large values of [ital G][approx gt]15, backward SBS dominates and prevents both self-focusing and forward SBS. For smaller values of [ital G], the interaction exhibits a complex oscillatory behavior, which corresponds to the competition between backward and forward SBS for [alpha][sub [ital sf]][approx lt]1, and involves also self-focusing for higher beam intensities.

• OSTI ID: 6022024
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 5:10; ISSN 0899-8221; ISSN PFBPEI
• Country of Publication: United States
• Language: English

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