Performance of a Helicon Hall Thruster Operating with Xenon, Argon, and Nitrogen

Abstract

The Helicon Hall Thruster (HHT) is a two-stage thruster that was developed to investigate whether a radiofrequency ionization stage can improve the overall efficiency of a Hall thruster operating at high thrust and low specific impulse. This experiment measured the single-stage and two-stage performance of the HHT for 10-25 mg/s anode mass flow rates of xenon at 100-200 V discharge voltages, and also for 6 mg/s of argon at 300 V, and 2.6 mg/s of nitrogen at 200 V. Argon and nitrogen performance are characterized by low beam divergence efficiency and low propellant utilization efficiency. During two-stage operation, the thrust of the HHT increased slightly with rf power, but the propulsive efficiency and thrust-to-power both decreased with increasing rf power. Probe diagnostics suggest that gains were realized by a slight increase in propellant efficiency, but that the rate of increase was not sufficient to overcome the increase in power.