Experimental studies of anode sheath phenomena in a hall thruster.

Conference · Thu Jan 01 04:00:00 EST 2004

DOI:https://doi.org/10.2172/836481· OSTI ID:977923

Dorf, L A ^[1]; Fisch, N J; Raitses, Yevgeny F

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1. Leonid A.

Both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in a Hall thruster were identified experimentally by performing accurate, non-disturbing near-anode measurements with biased and emissive probes. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. Probe measurements in a Hall thruster with three different magnetic field configurations show that an anode fall at the clean anode is a function of the radial magnetic field profile inside the channel. A positive anode fall formation mechanism suggested in this work is that: (1) when the anode front surface is coated with dielectric, a discharge current closes to the anode at the surfaces that remain conductive, (2) a total thermal electron current toward the conductive area is significantly smaller than the discharge current, therefore an additional electron flux needs to be attracted toward the conductive surfaces by the electronattracting sheath that appears at these surfaces.

• Research Organization: Los Alamos National Laboratory
• Sponsoring Organization: DOE
• OSTI ID: 977923
• Report Number(s): LA-UR-04-7851
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANODES
DIELECTRIC MATERIALS
ELECTRONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
PHYSICS
PLASMA
PROBES
REMOVAL
THRUSTERS