Saturation of stimulated Brillouin backscattering in two-dimensional kinetic ion simulations
- Lawrence Livermore National Laboratory, University of California, P.O. Box 808, Livermore, California 94551 (United States)
Two-dimensional simulations with a hybrid code (kinetic particle ions and Boltzmann fluid electrons) have been used to investigate the saturation of stimulated Brillouin backscatter (SBBS) instability. The simulations address the interplay of wave breaking and ion trapping (and the associated nonlinear frequency shift of the ion wave and nonlinear modification of the kinetic dissipation), two-ion-wave decay instability, harmonic generation, and pump depletion in affecting SBBS saturation as a function of the population of resonant ions, which is controlled by ZT{sub e}/T{sub i} in a single ion species plasma (Z is the ion charge state and T{sub e,i} are the electron and ion temperatures). The role of ponderomotive filamentation in these simulations is also examined. The peak SBBS reflectivities in two dimensions relax to values that are much less than in one dimension. Two-dimensional physics facilitates higher ion wave dissipation rates (including significant residual ion Landau damping) that account for the relaxation and suppression of SBBS.
- OSTI ID:
- 20722094
- Journal Information:
- Physics of Plasmas, Vol. 12, Issue 5; Other Information: DOI: 10.1063/1.1878792; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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