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Local Neutral Density and Plasma Parameter Measurements in a Hollow Cathode PlumeIn order to understand the cathode and keeper wear observed during the Extended Life Test (ELT) of the DS1 flight spare NSTAR thruster and provide benchmarking data for a 2D cathode/cathode-plume model, a basic understanding of the plasma and neutral gas parameters in the cathode orifice and keeper region of the cathode plume must be obtained. The JPL cathode facility is instrumented with an array of Langmuir probe diagnostics along with an optical diagnostic to measure line intensity of xenon neutrals. In order to make direct comparisons with the present model, a flat plate anode arrangement was installed for these tests. Neutral density is deduced from the scanning probe data of the plasma parameters and the measured xenon line intensity in the optical regime. The Langmuir probes are scanned both axially, out to 7.0 cm downstream of the keeper, and radially to obtain 2D profile of the plasma parameters. The optical fiber is housed in a collimating stainless steel tube, and is scanned to view across the cathode plume along cuts in front of the keeper with a resolution of 1.5 mm. The radial intensities are unfolded using the Abel inversion technique that produces radial profiles of local neutral density. In this paper, detailed measurements of the plasma parameters and the local neutral densities will be presented in the cathode/keeper plume region for a 1.5 cm diameter NEXIS cathode at 25A of discharge current at several different strengths of applied magnetic field.
Document ID
20060051443
Acquisition Source
Jet Propulsion Laboratory
Document Type
Preprint (Draft being sent to journal)
External Source(s)
Authors
Jameson, Kristina K.
(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)
MiKellides, Joannis
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Watkins, Ron M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Spacecraft Propulsion And Power
Meeting Information
Meeting: 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit
Location: Sacramento, CA
Country: United States
Start Date: July 9, 2006
End Date: July 12, 2006
Distribution Limits
Public
Copyright
Other
Keywords
Plasma density
ion thruster
electric propulsion

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