Active stabilization of a magnesium hall thruster in constant voltage mode

Document Type

Conference Proceeding

Publication Date

1-1-2011

Abstract

The direct-evaporation magnesium Hall thruster exhibits thermal runaway when operated in voltage-limited mode. This paper reports on a method of controlling runaway mass flow by manipulating the pre-set current and voltage limits of the anode power supply. By choosing proper voltage and current limits, voltage-limited operation was achieved for periods of greater than 9 minutes without any active control scheme. Natural cyclic transitions into and out of voltage-limited mode with a period of a few minutes were observed and are attributed to a time delay between onset of power increase and temperature rise in the propellant. By adjusting the current and voltage limits, both the amplitude and the frequency of the cyclic oscillations were reduced such that the thruster was semi-stable. From this semi-stable operating, point minor adjustments in the current to the electromagnets allowed true stabilization of the thruster discharge. Using this control scheme voltage-limited operation at 225 V and 5 A was sustained for more than an hour. copy; 2011 by Lyon B. King.

Publication Title

47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2011

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