Date of Award


Document Type


Degree Name

Master of Science


Department of Aeronautics and Astronautics

First Advisor

David Liu, PhD.


Experiments were performed at AFIT to determine the effect of active control of the magnetic field strength to reduce the breathing mode oscillation on the efficiency of a 200W Hall thruster. The breathing mode oscillation amplitude was measured by the root mean square (RMS) variation in the AC portion of the discharge current. Experiments were run using krypton and xenon propellant. Using the xenon propellant control of the RMS improved the propellant utilization efficiency by approximately 2% in two cases, while reducing the magnet current efficiency by about 10%. Control of the RMS's effect on the divergence angle of the plume was unable to be determined due to error. The overall effect was to decrease the total efficiency by about 5%. Using krypton, the effect on the propellant utilization was unable to be determined due to error. Control of the RMS decreased the magnet current efficiency by about 11%. The divergence angle was reduced by about 3°, resulting in an overall decrease in total efficiency of about 6%. Overall, utilizing control of the RMS can be useful in satellites whose payload requires more power than the thruster, as they would be able to make use of the increase in propellant utilization without exceeding power capabilities.

AFIT Designator


DTIC Accession Number