SPATIOTEMPORAL EVOLUTION OF PARAMETRIC-INSTABILITIES DRIVEN BY SHORT LASER-PULSES - 2-DIMENSIONAL ANALYSIS

The spatiotemporal evolution of parametric instabilities such as stimu lated Raman scattering is studied analytically in time and two spatial dimensions. Initial and boundary conditions are chosen to represent t he entrance, propagation, and exit of a laser pulse of finite extent c onvecting through a homogeneous collisional plasma with definite bound aries. 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 ne ar backward scattering. The sideward convection alters the spatiotempo ral character of the instability and inhibits but does not suppress it s growth. (C) 1997 American Institute of Physics.