Backward stimulated Brillouin scattering spatial gain with polarization, spatial, and temporal beam smoothing techniques

• Published in: Physics of plasmas 2023-12, Vol.30 (12)
• Main Authors: Ruyer, C., Fusaro, A., Capdessus, R., Debayle, A., Loiseau, P., Masson-Laborde, P. E., Morice, O.
• Format: Article
• Language: English
• Subjects: Differential equations; Laser plasmas; Magnetohydrodynamic stability; Modelling; Phase plates; Plasma physics; Polarization; Ray tracing; Scattering; Smoothing
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/5.0161176

A recent study [Ruyer et al., Phys. Rev. E 107, 035208 (2023)] modeling the influence of a random phase plate on the backward stimulated Brillouin scattering growth is here supplemented with the effect of temporal and polarization smoothing. Our analytical predictions are validated by a large number of three dimensional Hera paraxial simulations for various beam smoothing techniques and relevant to most high energy laser facilities. Neglecting all non-linear effects apart from the pump depletion, we then reconstruct the system of differential equations that the backward stimulated Brillouin scattering convective amplification of a smoothed beam propagating in a non-homogeneous plasma satisfies. Its resolution is successfully confronted with our simulation data and prepares the accurate modeling, in a ray tracing scheme, of the effect of laser smoothing techniques on laser plasma instabilities.