An analysis of energy balance in a helicon plasma source for space propulsion

Abstract

This thesis covers work done on the mHTX@MIT helicon source as it relates to the analysis of power losses. A helicon plasma is a rather complex system with many potential loss mechanisms. Among the most dominant are optical radiation emission, wall losses due to poor magnetic confinement, and poor antenna-plasma coupling. This work sought to establish a first-order breakdown of the loss mechanisms in the mHTX@MIT helicon source so as to allow for a better understanding of the issues effecting efficiency. This thesis proposes the use of a novel thermocouple array, standard plasma diagnostics, and a simple global energy balance model of the system to determine greater details regarding the losses incurred during regular operation. From this it may be possible, by comparing the heat flux on the tube to the applied magnetic field profile, to gain some insight into the effects of magnetic field geometry on the character of the helicon discharge.