Performance characterization of a low-power magnetically shielded Hall thruster with an internally-mounted hollow cathode

摘要

Magnetically shielded miniature (MaSMi) is a low power (?1 kW) long life (>100 kg Xe throughput) magnetically shielded Hall thruster that features an internally mounted hollow cathode. The development model MaSMi Hall thruster was designed, fabricated, and tested in preparation for advancement into an engineering model design. The MaSMi-DM uses an ultracompact internally-mounted heaterless hollow cathode, which has previously demonstrated stable operation over a discharge current range of 0.5–4 A. More than 100 heaterless ignitions were performed during this test campaign, revealing consistent and predictable start-up behavior. Component testing of a novel anode manifold used in the MaSMi-DM demonstrated peak-topeak azimuthal propellant flow distribution variations of less than 3.2% across three flow rates and two anodes. Current–voltage-magnetic field testing of the MaSMi-DM was completed over a discharge voltage range of 200–600 V, a discharge current range of 0.5–4.0 A, and a discharge power range of 150–1000 W. The MaSMi-DM demonstrated the highest total efficiency and highest total specific impulse of any sub-kW Hall thruster to date. Performance highlights include a peak thrust of 68.6 mN, a peak total specific impulse of 1940 s at 1000W with >1500 s available above 500 W, and a peak total efficiency of 54.2% at 1000W with >40% available above 300 W. Visual observations of the plasma discharge, carbon-coated discharge channel walls post-operation, and the results from plasma simulations provided strong evidence of magnetic shielding and the projected >100 kg Xe throughput capability of the thruster.