Saturation of Backward Stimulated Scattering of a Laser Beam in the Kinetic Regime

Journal Article · Mon Dec 31 04:00:00 EST 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.99.265004· OSTI ID:21028241

Yin, L; Albright, B J; Bowers, K J; Daughton, W; Rose, H A ^[1]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

Stimulated Raman (SRS) and Brillouin scattering (SBS) are examined in the kinetic regime using particle-in-cell simulations. Wave front bowing of electron-plasma waves (ion-acoustic waves) from trapped particle nonlinear frequency shift is observed in the SRS (SBS) regime for the first time. Self-focusing from trapped particle modulational instability (TPMI) is shown to occur in 2D and 3D SRS simulations. The key physics of SRS saturation is identified as a combination of wave front bowing, TPMI, and self-focusing: Bowing marks the beginning of SRS saturation and self-focusing terminates SRS. Ion-acoustic wave bowing also contributes to SBS saturation. Velocity diffusion by transverse modes and rapid loss of hot electrons in regions of small transverse extent formed from self-focusing dissipate wave energy and increase Landau damping, despite trapping that reduces Landau damping initially.

• OSTI ID: 21028241
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 26 Vol. 99; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BRILLOUIN EFFECT
ELECTRON PLASMA WAVES
FOCUSING
ION ACOUSTIC WAVES
LANDAU DAMPING
LASERS
PLASMA INSTABILITY
PLASMA SIMULATION
RAMAN EFFECT
TRAPPING