Theory and simulation of multibeam stimulated Raman scattering in inertial confinement fusion

Collective effects of multibeam laser plasma interactions are of great interests in recent years [1,2,3]. Here, we have demonstrated a general theory of multibeam stimulated Raman scattering (SRS) with arbitrary beam number and beam polarization incident in a cone geometry in both homogeneous and inhomogeneous plasma. Scattering geometry with a shared Langmuir wave or a shared electromagnetic wave are the ones that with the maximum growth rates as predicted by DuBois et al [4]. In addition to those scattering geometries, cone scattering where scattered lights perpendicular to the cone axis is dominant over common wave geometry in the nonlinear stage. In particle-in-cell simulations we have verified the effects of three scattering geometries, and obtained the density and incident angle dependence of the effects of multibeam SRS relevant to the indirect-drive ignition conditions. [1] S. Depierreux et al., Phys. Rev. Lett. {\bf 117}, 235002 (2016). [2] P. Michel et al., Phys. Rev. Lett. {\bf 115}, 055003 (2015). [3] E. L. Dewald et al., Phys. Rev. Lett. {\bf 116}, 075003 (2016). [4] D. F. DuBois, B. Bezzerides, and H. A. Rose, Phys. Fluids B {\bf 2}, 241 (1992).