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Magnetic Shielding of the Channel Walls in a Hall Plasma AcceleratorIn a qualification life test of a Hall thruster it was found that the erosion of the acceleration channel practically stopped after approx 5,600 h. Numerical simulations using a two-dimensional axisymmetric plasma solver with a magnetic field-aligned mesh reveal that when the channel receded from its early-in-life to its steady-state configuration the following changes occurred near the wall: (1) reduction of the electric field parallel to the wall that prohibited ions from acquiring significant impact kinetic energy before entering the sheath, (2) reduction of the potential fall in the sheath that further diminished the total energy ions gained before striking the material, and (3) reduction of the ion number density that decreased the flux of ions to the wall. All these changes, found to have been induced by the magnetic field, constituted collectively an effective shielding of the walls from any significant ion bombardment. Thus, we term this process in Hall thrusters "magnetic shielding."
Document ID
20120013809
Acquisition Source
Jet Propulsion Laboratory
Document Type
Reprint (Version printed in journal)
Authors
Mikellides, Ioannis G.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Katz, Ira
(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)
Goebel, Dan M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
deGrys, Kristi
(Aerojet-General Corp. Redmond, WA, United States)
Mathers, Alex
(Aerojet-General Corp. Redmond, WA, United States)
Date Acquired
August 26, 2013
Publication Date
March 8, 2011
Publication Information
Publication: Physics of Plasmas
Volume: 118
Issue: 3
Subject Category
Spacecraft Propulsion And Power
Distribution Limits
Public
Copyright
Other
Keywords
ion density
plasma accelerators
plasma magnetohydrodynamics
magnetic shielding

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