TY - GEN
T1 - Simulations of fast electron generation by stimulated Raman forward scattering in a magnetized plasma
AU - Bertrand, Pierre
AU - Ghizzo, Alain
AU - Karttunen, Seppo
AU - Pättikangas, Timo
AU - Salomaa, Rainer
AU - Shoucri, M.
N1 - Project code: ydi9006
PY - 1992
Y1 - 1992
N2 - 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.
AB - 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.
M3 - Conference article in proceedings
VL - 2
T3 - Europhysics Conference Abstracts
SP - 1005
EP - 1008
BT - 1992 International Conference on Plasma Physics
A2 - Freysinger, W.
A2 - Lackner, K.
A2 - Schrittwieser, R.
A2 - Lindinger, W.
PB - European Physical Society
T2 - 1992 International Conference on Plasma Physics
Y2 - 29 June 1992 through 3 July 1992
ER -