Study of growth rate of backward Raman scattering in plasma with density ripple

Abstract

The recent studies proved that stimulated backward Raman scattering of a laser is affected significantly by the existence of magnetic field and density rippled plasma. At lower hybrid frequencies, the localized radial and azimuthal modes can be supported by the magnetized plasma. The density ripple interacts with the Raman process’s main Langmuir wave, producing in a secondary Langmuir wave with a higher wave number that is highly Landau damped on the electrons. Numerically, the influence of various modes on the growth rate revealed that the ripple and local effects greatly decrease the growth rate of stimulated Raman backscattering. As a result, the Raman process is controlled by the magnetized density rippled plasma and the growth rate is reduced significantly.

Stimulated Raman scattering by circularly polarized quadruple Gaussian laser beam and co-propagating electron beam in plasma

“…The intricate interplay between laser and plasma gives rise to a host of nonlinear phenomena, including self-focusing of propagating beams [7][8][9][10][11][12], filamentation [13], self-phase modulation [14], finite pulse effect [15], second harmonic generation [16], as well as the emergence of parametric instabilities [17] such as stimulated Brillouin scattering, stimulated Raman scattering (SRS) [18][19][20] and two-plasmon decay [21]. During the propagation of a laser beam through plasma, a portion of its energy is reflected due to the presence of various parametric instabilities, which assume critical significance in the context of ICF.…”