Performance of double-stage-discharge Hall ion thruster

Abstract

A Hall ion thruster was experimentally studied with the objective of improving the performance and better understanding acceleration and ion production mechanisms. It was experimentally confirmed in this study that the low efficiency of the single-stage configuration of this thruster was attributed to the low energy transfer ratio and the poor stability of the discharge in a strong magnetic field. These faults were overcome by the plasma source at the upstream end of the acceleration region in the double-stage configuration. The performance obtained with this improvement was 9-mN thrust, 70% propeliant utilization efficiency, 600-eV/ion ion production cost, and 13% total efficiency at 1800-s specific impulse. Moreover, it was confirmed from the comparison between experimental results and theoretical analysis that the low acceleration efficiency in the Hall ion thruster may be caused by the anomalous electron back flow due to Bohm diffusion and the loss of ions to the wall.