A Study on Arc Instability Phenomena of a Hollow Cathode Plasma Torch in a Low Pressure Environment

This study investigates arc instability phenomena associated with hollow-cathode plasma torches under low pressure. Stable and unstable regimes are evaluated based on Fourier analysis of gun voltage. For comparison, arc fluctuations with a solid-cathode torch are studied as well. Different internal hardware configurations are used during spraying to identify and assess important factors in the design of hollow and solid cathode guns. This work also characterizes a number of parameters that would exploit plume elongation and accelerated gas velocities under low-pressure conditions.