Angular dependence of stimulated Brillouin scattering in homogeneous plasma

The angular dependence of stimulated Brillouin scattering (SBS) in a finite homogeneous plasma is studied. For parameters typical of inertial confinement fusion experiments, the initial evolution of SBS is well approximated by a one-dimensional model. In the context of this linear model, the threshold intensity of the absolute instability and the steady-state spatial growth rate of the convective instability are both independent of the scattering angle. However, the saturation time of the convective instability exhibits a strong inverse dependence on the scattering angle: Forward SBS always occurs in the transient regime and the intensity of the scattered light is less than that predicted by a steady-state analysis. In particular, no light is emitted in the propagation direction of the incident wave.