Parameter scan of stimulated Raman scattering in magnetic fields*

Stimulated Raman scattering (SRS) can be mitigated in the kinetic regime (kλ_D > ~0.3) by weak magnetic fields (ω_c/ω_p << 1) due to the damping of electron plasma waves (EPWs) propagating perpendicular to the magnetic fields.  However, we have also found that magnetic fields can interfere with the nonlinear frequency shift of SRS-driven EPWs, and for SRS that is dominated by the dynamics of this frequency shift, magnetic fields can thereby indirectly enhance the frequency resonance between the light and plasma waves involved in SRS.  Furthermore, in some parameter regimes, the SRS waves can themselves be unstable (e.g. the backscattered light wave can decay via rescatter and the backscattered EPW can decay via LDI), and for finite-width waves in multi-dimensions, the damping and transverse evolution of SRS EPWs depends sensitively on wave-particle interactions that can be impacted by magnetic fields.  We show particle-in-cell simulations that illustrate how magnetic fields impact SRS and EPWs across a wide range of laser and plasma parameters.