Vlasov-Maxwell simulation of simultaneous stimulated Raman forward and backward scattering

Pierre Bertrand, Seppo Karttunen, Timo Pättikangas, Alain Ghizzo, Rainer Salomaa, Magdi Shourcri

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

    Abstract

    In stimulated Raman scattering (SRS), an electromagnetic pump wave decays into a scattered wave and a plasma wave. In long nearly uniform plasmas, the electrostatic fields may reach large amplitudes and thus trap and accelerate electrons to high energies. In laser fusion, even a small number of energetic electrons can cause severe preheating and thus prevent the efficient compression of the fuel capsule. In magnetic fusion, the beat wave process or SRS in the microwave region can be applied to current drive in tokamaks. In current drive, collisionless fast electrons are beneficial. Both in Raman forward (SRS-F) and backward scattering (SRS-B); the electron plasma waves travel forwards but their phase velocities can differ considerably. In most laser-plasma experiments, SRS-B dominates over SRS-F because of its larger gain. In well-underdense high-temperature plasmas, however, the Landau damping strongly limits SRS-B, which allows the growth of SRS-F. In some cases, solely SRS-F is excited. The parameters corresponding to reactor-grade laser-plasma experiments and to SRS current drive in fusion reactors lie in an intermediate region where both processes can occur simultaneously. The coupled mode theory predicts that in a homogeneous plasma slab, SRS-B and SRS-F, and correspondingly the respective plasma waves, are localized in spatially distinct regions: SRS-B in the front and SRS-F in the rear part of the plasma slab.
    Original languageEnglish
    Title of host publication20th EPS Conference on Controlled Fusion and Plasma Physics
    Place of PublicationLisboa
    PublisherEuropean Physical Society
    Pages1245-1248
    Volume4
    Publication statusPublished - 1993
    MoE publication typeA4 Article in a conference publication
    Event20th EPS Conference on Controlled Fusion and Plasma Physics - Lissabon, Portugal
    Duration: 26 Jul 199330 Jul 1993

    Publication series

    SeriesEurophysics Conference Abstracts
    Volume17C
    ISSN0378-2271

    Conference

    Conference20th EPS Conference on Controlled Fusion and Plasma Physics
    Country/TerritoryPortugal
    CityLissabon
    Period26/07/9330/07/93

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