Forward Brillouin scattering of a spatially and temporally smoothed laser pulse in ICF conditions

The laser plasma interaction studies mostly address the back-scattering, the cross beam energy transfer or the energy deposition and subsequent transport. We propose to focus here on the forward scattering of an energetic laser beam, as used in most ICF facilities, off ponderomotively driven acoustic fluctuations. Proof will be made that, when accounting properly for the Landau damping of acoustic waves, the resulting scatter may present a f-cone angle significantly larger that the initial pump wave and able to affect the energy deposition in ICF conditions. The influence on the spatial growth of the instability of both the spatial (random phase plates) [1] and temporal (spectral dispersion) [2] smoothing techniques often used to improve the beam propagation control will be properly accounted for and discussed.

[1] C. Ruyer et al., Phys. Plasmas 28, 052701 (2021)

[2] C. Ruyer et al., in prep