Plasma heating in field-reversed theta pinches

Abstract

A method is devised to simulate plasma formation and heating in a field-reversed theta pinch which accounts for implosion kinetics, resistive dissipation, and compression (both radial and axial). Although containing several simplifying features, e.g., assumed radial profiles, distinct steps in the formation process, and a single adjustable parameter, the model nevertheless conserves energy and momentum in a global sense. Dissipation of reversed flux is governed by imposing an empirical ‘‘relaxation condition’’ on the drift parameter. Despite the simplicity of the method, predicted temperatures and radii agree well with experiments in most cases. The most important trend observed is the significant increase in temperature at higher reverse bias field. This arises from resistive dissipation and axial compression. In most cases, the predicted temperature exceeds (sometimes significantly) the temperature derived for a simple bounce and compression.