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Plasma Perturbations in High-Speed Probing of Hall Thruster Discharge Chambers: Quantification and MitigationAn experimental investigation is presented to quantify the effect of high-speed probing on the plasma parameters inside the discharge chamber of a 6-kW Hall thruster. Understanding the nature of these perturbations is of significant interest given the importance of accurate plasma measurements for characterizing thruster operation. An array of diagnostics including a high-speed camera and embedded wall probes is employed to examine in real time the changes in electron temperature and plasma potential induced by inserting a high-speed reciprocating Langmuir probe into the discharge chamber. It is found that the perturbations onset when the scanning probe is downstream of the electron temperature peak, and that along channel centerline, the perturbations are best characterized as a downstream shift of plasma parameters by 15-20% the length of the discharge chamber. A parametric study is performed to investigate techniques to mitigate the observed probe perturbations including varying probe speed, probe location, and operating conditions. It is found that the perturbations largely disappear when the thruster is operated at low power and low discharge voltage. The results of this mitigation study are discussed in the context of recommended methods for generating unperturbed measurements of the discharge chamber plasma.
Document ID
20170008216
Document Type
Conference Paper
External Source(s)
Authors
Jorns, Benjamin A. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Goebel, Dan M. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Hofer, Richard R. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 1, 2017
Publication Date
July 27, 2015
Subject Category
Spacecraft Propulsion and Power
Meeting Information
AIAA/SAE/ASEE Joint Propulsion Conference(Orlando, FL)
Distribution Limits
Public
Copyright
Other