Spatiotemporal evolution of parametric instabilities driven by short laser pulses: Two-dimensional analysis

The spatiotemporal evolution of parametric instabilities such as stimulated Raman scattering is studied analytically in time and two spatial dimensions. Initial and boundary conditions are chosen to represent the entrance, propagation, and exit of a laser pulse of finite extent convecting through a homogeneous collisional plasma with definite boundaries. For most scattering angles the growth is found to be dominated by two-dimensional effects with one-dimensional amplitudes being valid for only a small range of angles corresponding to near forward and near backward scattering. The sideward convection alters the spatiotemporal character of the instability and inhibits but does not suppress its growth. copyright 1997 American Institute of Physics