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

Abstract

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 1000 W with >1500 s available above 500 W, and a peak total efficiency of 54.2% at 1000 W 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.

Operation of a low-power Hall thruster: comparison between magnetically unshielded and shielded configuration

“…This thruster was extensively simulated with Hall2De to understand why such a low efficiency is achieved [20]. Lessons learned from this study have led to the construction of a secondary laboratory model (LM2) [21] as well as a demonstration model increasing its performance to 0.45 anode efficiency [22].…”

Plume Divergence and Discharge Oscillations of an Accessible Low-Power Hall Effect Thruster

“…The power spectral density for each of the swept voltages and magnet currents are shown in Figure 10. The characteristic oscillation frequency varied between 60 and 90 kHz for all operating conditions, which was higher than expected based on other similarly sized thrusters [19,20]. As discharge voltage was increased at the high flow condition, Figure 10a, the strongest oscillation frequency remained largely constant at about 60 kHz, and the spectral strength remained broadband throughout the range of discharge voltages swept.…”

Magnetic field deflection in a 100 W Hall thruster with permanent magnets

“…Electric propulsion (EP) has flourished with various propulsion devices in the past few decades [1][2][3][4][5][6][7]. Hall thrusters are one of the most widespread electrostatic acceleration EP devices generating and accelerating ions with orthogonal electric and magnetic fields.…”