Transverse beam envelope structures in strongly coupled stimulated Brillouin scattering

We use a newly developed code to investigate cross beam energy transfer via Brillouin scattering in the strong coupling limit. The code couples a single fluid model of the plasma to the complete set of Maxwell's equations. The code can describe beam interaction at arbitrary angles. We observe that the formation of a transverse structure on both beams is caused when the pump beam is fully depleted within the width of the beam. We present a simplified envelope model that confirms the results of the simulation. This transverse beam structure formation has implications for short pulse amplification. The results may also be relevant for fast ignition schemes for inertial confinement fusion.