Magnetic shielding of the channel walls in a Hall plasma accelerator
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
- Aerojet, Redmond, Washington 98052 (United States)
In a qualification life test of a Hall thruster it was found that the erosion of the acceleration channel practically stopped after {approx}5600 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'.
- OSTI ID:
- 21537324
- Journal Information:
- Physics of Plasmas, Vol. 18, Issue 3; Other Information: DOI: 10.1063/1.3551583; (c) 2011 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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