Effect of magnetic fields on the anisotropy of the distribution function of thermonuclear particles in LTF

Abstract

The spontaneous magnetic fields produced by compression of spherical laser targets are known to reach, through development of hydrodynamic instability, strengths on the order of several times ten MG and thereby influence substantially the kinetics of fast charged particles. The same can be said also of external magnetic fields, since the target compression causes the fields to increase at the instant of maximum compression by 100 to 500 times, owing to the freezing-in of the force lines. Thus, even at an initial field strength [approx]10[sup 2] kG, the fields can reach in the course of compression tens of MG and alter substantially the kinetics of the fast particles. The present paper is devoted to the development of a method of direct statistical simulation of the physics of distribution of fast charged particles -- products of thermonuclear reactions accompanying LTF (laser thermonuclear fusion) in magnetic fields of arbitrary configuration. The authors use this method to investigate the influence of the magnetic fields on the distribution function f(r, v) itself as well as the energy transfer from the fast thermonuclear particles to the background plasma of the target and also on the flux anisotropy in the energy spectra of the particles emittedmore » from the target. They propose for the diagnostics of the magnetic field in the target a method based on an analysis of the degree of anisotropy of the flows of the particles leaving the target. 13 refs., 15 figs.« less