Theory of filamentation instability and stimulated Brillouin scattering with nonlocal hydrodynamics

A linear theory of stimulated Brillouin scattering and filamentation instabilities has been formulated using nonlocal transport equations for a laser heated plasma, resulting in a model which is fully equivalent to a linearized kinetic description. The inverse-Bremsstrahlung heating, nonlocal energy redistribution, and ponderomotive laser–plasma interactions are correctly taken into account contributing to a new generalized driving force for these instabilities. Temporal and spatial growth rates, thresholds and dominant perturbation wavelengths are obtained. This theory predicts substantial modifications of the ponderomotive results for conditions relevant to many laser plasma interaction experiments. A new nonlocal and nonlinear model of laser propagation in weakly collisional plasmas has been derived.