Kinetic theory of laser filamentation in plasmas

Abstract

The classical theory of laser thermal filamentation in a homogeneous plasma has been extended to include the effects of nonlocal electron heat transport. The new theory reduces the instability threshold and predicts an optimum perturbation wavelength that maximizes the spatial growth. Theoretical predictions suggest that the thermal mechanism, rather than the ponderomotive one, may explain the experimental observation of filaments by Young et al. [Phys. Rev. Lett. 61, 2336 (1988)]. In general, for conditions typical of inertial-confinement fusion, the thermal filamentation instability is expected to dominate.