Stimulated forward Raman scattering of a laser in a magnetized plasma

Abstract

A Gaussian laser beam propagating through a low-density plasma in the presence of an azimuthal magnetic field undergoes stimulated forward Raman scattering producing a lower hybrid wave and two radially localized electromagnetic sideband waves. The radial widths of the sidebands are of the order of the spot size of the pump, whereas the radial width of the lower hybrid wave depends on the growth rate of the Raman process. The nonlocal effect arising, due to the azimuthal magnetic field, reduces the region of nonlocal interaction and hence the growth rate. The growth rate of stimulated Raman forward scattering first increases on increasing magnetic field, maximizes at some optimum value of magnetic field, and then decreases.

Stimulated forward Raman scattering in density rippled magnetized plasma

“…SRS is one of the most critical instabilities in laser-driven fusion because it disperses the incident laser energy and produces hot electrons [2,3,4,5]. The growth rate of stimulated forward Raman scattering decreases significantly when the lower hybrid wave is localised in the presence of an azimuthal magnetic field, according to Sajjal et al [6]. Similar studies on the impact of magnetic fields on SRS has shown that the instability's growth is significantly slowed [7,8].…”

Effect of chirp on stimulated-forward Raman scattering in a magnetised plasma with rippled density for fusion applications

“…Magnetization improved target performance and was also found to affect the hotspot spatial evolution. Studies observing the effect of magnetic fields on SRS have also found significant suppression of the instability's development [30][31][32].…”

Stimulated Raman scattering of laser in a plasma in the presence of a co-propagating electron beam

“…Kirkwood et al 21 have performed experiments on SRS with laser intensity and electron temperature relevant to ignition experiments. Sajal et al 22 have studied forward SRS of a Gaussian laser in a low density plasma in the presence of azimuthal magnetic field. They found that the azimuthal magnetic field reduces the region of nonlocal interaction and growth rate.…”