Experimental and theoretical characterization of a Hall thruster plume

Despite the considerable flight heritage of the Hall thruster, the interaction of its plume with the spacecraft remains an important integration issue. Because in-flight data fully characterizing the plume in the space environment are currently unavailable, laboratory measurements are often used to understand plasma expansion and thereby minimize adverse plume-spacecraft interactions. However, experimental measurements obtained in ground facilities do not properly capture the wide angle plume effects most important for plume-spacecraft interactions because of the high background pressure of the laboratory environment. This research describes a method to determine the in-orbit plume divergence of a Hall thruster from laboratory measurements and characterizes the plasma properties of the in-orbit plume. Plume measurements were taken with a Faraday probe and a Retarding Potential Analyzer at various background pressures to correlate changes in current density and ion energy distribution with changes in pressure. Results showed that current density increases linearly with background pressure at any given angle. This linear relationship was used to extrapolate laboratory measurements to zero background pressure, the in-orbit condition. Measurements from the Faraday probe and the Retarding Potential Analyzer were compared to ensure consistency. The effect of discharge voltage on plume divergence was also investigated. Measurements from both probes revealed that plume divergence decreases with an increase in discharge voltage. Hall thruster plume expansion was also characterized using a numerical plume simulation. Comparison of plume simulation results for in-orbit conditions to extrapolated current density at zero pressure demonstrated good agreement.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Aeronautics and Astronautics

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Azziz, Yassir, 1979-

Advisor dc:contributor.advisor

• Manuel Martinez-Sanchez.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40856

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40856