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Effect of small normalized magnetic fields on rescatter of stimulated Raman scattering in the kinetic regime

POSTER

Abstract

We have previously shown [1] how backward stimulated Raman scattering (SRS) in the kinetic regime (kλDe ≈ 0.30 for backward SRS scattered plasma wave) can be mitigated by weak magnetic fields (ωc/ωp << 1) due to enhanced damping of non-linear electron plasma waves. In this presentation, we show results of 1D and 2D OSIRIS simulations of SRS in the kinetic regime for unmagnetized and magnetized plasmas at densities low enough (ne/nc < 11%) such that rescatter (backscattered light wave itself backscatters) is possible. We show that for these parameters, the magnetic field can enhance time averaged reflectivity of backward SRS by modifying plasma conditions and suppressing rescatter. Specifically, the magnetic field supresses rescatter by heating the plasma around the phase velocity of rescatter plasma waves, thereby increasing their damping and lowering the growth rate for rescatter. We present theoretical calculations which support this by indicating that these weak magnetic fields cause a transition of the rescatter instability from an undamped regime to a strongly damped regime.

References:

[1] B. J. Winjum, et al. Phys. Rev. E 98, 043208 (2018)

Publication: Lee et al., in preparation (2022)

Presenters

  • Roman Lee

    University of California, Los Angeles

Authors

  • Roman Lee

    University of California, Los Angeles

  • Benjamin J Winjum

    University of California, Los Angeles

  • SJ Spencer

    University of California, Los Angeles, University of Warwick

  • Mathieu Bailly-Grandvaux

    University of California, San Diego

  • Simon Bolanos

    UCSD, University of California, San Diego

  • Mario Manuel

    General Atomics - San Diego

  • Frank S Tsung

    University of California, Los Angeles

  • Farhat N Beg

    University of California, San Diego

  • Warren B Mori

    University of California, Los Angeles, Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA