Effects of preformed plasma of CH foam on fast electron generation

Abstract

In fast ignition, the intensity of an unavoidable pre-pulse of a heating laser is still high to generate plasmas even if the contrast ratio is high. So, a preformed plasma (pre-plasma) is created before a main pulse of the heating laser irradiates a target. The recent research suggests that coating an inner surface of the cone of the cone-guided target with the low-density foam enhances fast electron generation. But the pre-plasma and the foam structure, which consists of dense CH plasmas and voids, are ignored in that research. In this paper, effects of the pre-plasma and the foam structure on the fast electron generation are investigated with the use of an one-dimensional Particle-In-Cell code. It is found that effects of the pre-plasma on the fast electron generation are small and the foam structure weakens the generation of fast electrons with the moderate energy.