Feasibility study for using an extended three-wave model to simulate plasma-based backward Raman amplification in one spatial dimension

Abstract

Breakdown of electrostatic predictions for the nonlinear dispersion relation of a stimulated Raman scattering driven plasma wave Phys. Plasmas 15, 030701 (2008); 10.1063/1.2888515 Self-induced transparency scenario revisited via beat-wave heating induced by Doppler shift in overdense plasma layer Results are reported of a one-dimensional simulation study comparing the modeling capability of a recently formulated extended three-wave model ͓R. R. Lindberg, A. E. Charman, and J. S. Wurtele, Phys. Plasmas 14, 122103 ͑2007͒; Phys. Plasmas 15, 055911 ͑2008͔͒ to that of a particle-in-cell ͑PIC͒ code, as well as to a more conventional three-wave model, in the context of the plasma-based backward Raman amplification ͑PBRA͒ ͓G. Shvets, N. J. Fisch, A. Pukhov et al., Phys. Rev. Lett. 81, 4879 ͑1998͒; V. M. Malkin, G. Shvets, and N. J. Fisch, Phys. Rev. Lett. 82, 4448 ͑1999͒; Phys.Rev. Lett. 84, 1208 ͑2000͔͒. The extended three-wave model performs essentially as well as or better than a conventional three-wave description in all temperature regimes tested, and significantly better at the higher temperatures studied, while the computational savings afforded by the extended three-wave model make it a potentially attractive tool that can be used prior to or in conjunction with PIC simulations to model the kinetic effects of PBRA for nonrelativistic laser pulses interacting with underdense thermal plasmas. Very fast but reasonably accurate at moderate plasma temperatures, this model may be used to perform wide-ranging parameter scans or other exploratory analyses quickly and efficiently, in order to guide subsequent simulation via more accurate if intensive PIC techniques or other algorithms approximating the full Vlasov-Maxwell equations.

Nonlinear kinetic description of Raman growth using an envelope code, and comparisons with Vlasov simulations

“…It therefore seems that our modeling would be more appropriate to large temperature plasmas than that of Lindberg et al Actually, it was pointed out in Ref. 30 We also account in our modeling for the nonlinear change in the EPW group velocity and our theoretical predictions for the nonlinear values of v gp were carefully checked against Vlasov simulations in Ref. 31.…”

“…The results of this model were moreover compared to those derived from PIC simulations in Ref. 30, when k p D Ͻ 0.3.…”

New criteria for efficient Raman and Brillouin amplification of laser beams in plasma

“…for a non-constant pump amplitude, or beyond the traditional wave-breaking limit, or in warm plasma, or for particle-in-cell computer simulations that do not know anything about three-wave models. This is needed to verify that the -pulse shape for the seed pulse is still likely to be an attractor in practical situations, which is often stated but never proved 6 , 36 . We will explore this below and in the Supplementary Information 27 .…”

Limiting effects on laser compression by resonant backward Raman scattering in modern experiments

“…A fully kinetic description of nonlinear Landau damping is a challenging task both numerically and analytically. A number of reduced analytical models [47][48][49] as well as simplified codes [50][51][52] describing nonlinear Landau damping of a driven plasma wave were recently offered. The quasilinear model described in Ref.…”