TY - GEN
T1 - Vlasov-Maxwell simulation of simultaneous stimulated Raman forward and backward scattering
AU - Bertrand, Pierre
AU - Karttunen, Seppo
AU - Pättikangas, Timo
AU - Ghizzo, Alain
AU - Salomaa, Rainer
AU - Shourcri, Magdi
PY - 1993
Y1 - 1993
N2 - 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.
AB - 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.
M3 - Conference article in proceedings
VL - 4
T3 - Europhysics Conference Abstracts
SP - 1245
EP - 1248
BT - 20th EPS Conference on Controlled Fusion and Plasma Physics
PB - European Physical Society
CY - Lisboa
T2 - 20th EPS Conference on Controlled Fusion and Plasma Physics
Y2 - 26 July 1993 through 30 July 1993
ER -