Simulations of fast electron generation by stimulated Raman forward scattering in a magnetized plasma

Pierre Bertrand, Alain Ghizzo, Seppo Karttunen, Timo Pättikangas, Rainer Salomaa, M. Shoucri

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    Stimulated Raman scattering (SRS) of free-electron-laser (FEL) radiation can be applied to the current drive in tokamak plasmas, because SRS generates nearly collisionless electrons with high parallel velocities. The scattered electromagnetic (EM) wave in SRS may propagate either backward (SRS-B) or forward (SRS-F). The electron plasma wave, which produces fast electrons by Landau coupling, travels in both cases in the same direction as the pump wave. The phase velocity of the plasma wave, and correspondingly the fast electron energy, in SRS-B is much lower than in SRS-F. At high temperatures and low densities, the plasma wave excited in SRS-B is heavily damped so that the Raman forward scattering prevails in long scalelength plasmas. We present simulations performed with an Eulerian relativistic Vlasov code. Such a code renders possible a detailed examination of the low density regions of the phase-space, which are poorly described by the usual PIC codes. A second advantage is the noiseless character of the code, due to its Eulerian type. SRS-F is considered in the parameter range where the phase velocity of the electrostatic plasma wave exceeds 0.9c. The corresponding energy of the fast electrons is highly relativistic, i.e., γ=(1-vph2/c2)-1/2>2.3. Our simulations reveal that the plasma waves in this range are, in fact, able to produce even more energetic electrons, up to γ≅4-12.
    Original languageEnglish
    Title of host publication1992 International Conference on Plasma Physics
    EditorsW. Freysinger, K. Lackner, R. Schrittwieser, W. Lindinger
    PublisherEuropean Physical Society
    Pages1005-1008
    Volume2
    Publication statusPublished - 1992
    MoE publication typeA4 Article in a conference publication
    Event1992 International Conference on Plasma Physics - Innsbruck, Austria
    Duration: 29 Jun 19923 Jul 1992

    Publication series

    SeriesEurophysics Conference Abstracts
    Volume16B
    ISSN0378-2271

    Conference

    Conference1992 International Conference on Plasma Physics
    CountryAustria
    CityInnsbruck
    Period29/06/923/07/92

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