Finite Larmor radius corrections have been considered in the effects of strong magnetic fields on stimulated Raman scattering. A nonlinear dispersion relation describing the various channels of decay has been derived from the Vlasov-Maxwell equations and frequencies and growth rates determined for the decay of incident laser light in the extraordinary mode into scattered extraordinary mode radiation and electron Bernstein waves. A relativistic one-and-a-half dimensional particle code has been used to simulate the scattering process and the results from the numerical experiments have been compared with those obtained analytically, the agreement being generally good. Growth rates of the Bernstein waves are substantial when sufficiently strong magnetic fields are present in hot plasmas. Under these conditions the kinetic analysis shows that, in contrast to the predictions of fluid theory, the scattered light emitted from densities well below the quarter-critical layer can have a frequency less than ½ω0 where ω0 is the laser frequency. In an unmagnetized plasma this occurs only when the plasma has a finite temperature.
Mitigation of stimulated Raman scattering in the kinetic regime by external magnetic fields