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Published November 14, 2021 | Published
Journal Article Open

Use of an accelerated testing method to characterize inner front pole cover erosion in a high power Hall thruster

Abstract

Erosion characteristics on the cover of the inner front pole in a 12.5 kW Hall thruster were measured over a wide range of operating conditions in tests of 6–14 h duration using an accelerated test method and a very sensitive, radioactive tracer-based erosion diagnostic. The operating points included the nominal 300–600 V conditions on a constant 20.8 A throttle curve and conditions at other currents spanning the throttling envelope and with varying magnetic field strength, facility pressure, and discharge voltage oscillation amplitude. Surprisingly, the results show that the highest wear rates occur at the lowest voltages and currents. The wear rates were insensitive to discharge voltage ripple but increased monotonically with magnetic field strength, particularly near the inner radius of the pole cover. The inner region was also sensitive to facility pressure, showing lower rates at a higher pressure level. Separate experiments in which the energy distributions of ions generated by the hollow cathode were measured suggest that the cathode plume may be a source of energetic ions responsible for some of the erosion trends, in addition to ions originating in the thruster plume.

Additional Information

© 2021 Author(s). Published under an exclusive license by AIP Publishing. Submitted: 16 August 2021; Accepted: 12 October 2021; Published Online: 9 November 2021. The support of the joint NASA GRC and JPL development of HERMeS by NASA's Space Technology Mission Directorate through the Solar Electric Propulsion Technology Demonstration Mission project is gratefully acknowledged. The authors would also like to acknowledge the assistance of Yves Trudeau at ANS Technologies in planning for and activating the parts used in these experiments. The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (No. 80NM0018D0004). Data Availability: The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Created:
October 5, 2023
Modified:
October 24, 2023