Study of the Plasma-Wall Interface – Measurement and Simulation of Sheath Potential Profiles Samuel J. Langendorf, Mitchell L.R. Walker High-Power Electric Propulsion Laboratory, Georgia Institute of Technology, Atlanta, GA 30332 USA Laura P. Rose, Michael Keidar Micropropulsion and Nanotechnology Laboratory, George Washington University, Washington, D.C. 20052 USA Lubos Brieda Particle in Cell Consulting LLC, Falls Church, VA 22046 49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 14 -17 July 2013, San Jose, California
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Study of the Plasma-Wall Interface – Measurement and Simulation of Sheath Potential Profiles
Study of the Plasma-Wall Interface – Measurement and Simulation of Sheath Potential Profiles. Samuel J. Langendorf, Mitchell L.R. Walker High-Power Electric Propulsion Laboratory, Georgia Institute of Technology, Atlanta, GA 30332 USA Laura P. Rose, Michael Keidar - PowerPoint PPT Presentation
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Study of the Plasma-Wall Interface – Measurement and Simulation of
Sheath Potential Profiles Samuel J. Langendorf, Mitchell L.R. Walker
High-Power Electric Propulsion Laboratory, Georgia Institute of Technology, Atlanta, GA 30332 USA
Laura P. Rose, Michael KeidarMicropropulsion and Nanotechnology Laboratory, George
Washington University, Washington, D.C. 20052 USA
Lubos Brieda Particle in Cell Consulting LLC, Falls Church, VA 22046
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 14 -17 July 2013, San Jose, California
– Observed sheaths in agreement with shape predicted by theory and simulation, but larger
• Believed due to incomplete knowledge of EEDF– Experimentally verified that SEE can alter both size and
shape of sheath potential profile and cause sheath disappearance
• Mechanism for increased energy loss to the wall
• Future Work– Improve Langmuir probe measurement to get EEDF– Incorporate measured EEDF into simulation– Measure SEE sheath with increased spatial resolution– Develop simulation of effects of SEE
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Conclusions
• Acknowledgements– This work is supported by the Air Force Office
of Scientific Research through Grant FA9550-11-10160
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Conclusions
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Experimental Method
Axial distance from magnet (in)
Radial distance from magnet (in)
Magnetic Field
Bulk plasma largely field-free
(G)
Gaussmeter 200
180
160
140
120
100
80
60
40
20
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.00.0 0.2 0.4 0.6 0.8 1.0 1.2
Background
SEE Yield
Al2O3 = High SEEBN = Med SEE
3Viel-Inguimbert, V. "Secondary electron emission of ceramics used in the channel of SPT." IEPC-2003-258, Toulouse, France. 2003.