A laser plasma interaction model for the conditions of stimulated Brillouin backscattering model experiments

Abstract

A model of laser interaction with a preformed target plasma is developed for the conditions of so called stimulated Brillouin backscattering (SBS) model experiments and its applicability is demonstrated by various tests. Most of the features can be understood from analytical approximations. A consequence of irradiation by a narrow beam, typical of model experiments, is the stabilization of electron temperature at low values. Another consequence equally unexpected is the SBS threshold dependence on beam radius and the particular power law dependence on plasma density. On the basis of this model the wide scatter of the SBS threshold between model experiments can be explained. It is also demonstrated that, for the conditions of these model experiments, classical Spitzer heat conduction suffices.