Enhancement and mitigation of kinetic stimulated Raman scattering by a magnetic field*

Stimulated Raman scattering (SRS) can be mitigated in the kinetic regime (kλ_De > ~0.3) by a weak magnetic field (ω_c/ω_p << 1) due to the damping of electron plasma waves (EPWs) propagating perpendicular to the magnetic field.  However, the effect of the magnetic field on trapped particle motion can alter not only the damping of daughter EPWs in SRS, it can also impact their frequency and wave envelope, and it can alter the particle population that resonantly interacts with other potential decay waves in the system.  We show one- and two-dimensional particle-in-cell simulations that illustrate how weak magnetic fields impact nonlinear EPWs and SRS across a wide range of laser and plasma parameters, and we illustrate how an imposed magnetic field can mitigate SRS for some regimes but enhance SRS for others.