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Title: Anode Fall Formation in a Hall Thruster

Abstract

As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. 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. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed.

Authors:
; ; ;
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC) (US)
OSTI Identifier:
828266
Report Number(s):
PPPL-3975
TRN: US0403892
DOE Contract Number:  
AC02-76CH03073
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 29 Jun 2004
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANODES; CHEMICAL COMPOSITION; COATINGS; DIELECTRIC MATERIALS; ELECTRON TEMPERATURE; OXIDES; OXYGEN; PLASMA DENSITY; PLASMA POTENTIAL; PROBES; REMOVAL; SPECTROSCOPY; THRUSTERS; PLASMA DYNAMICS; SHEATH; HALL THRUSTERS

Citation Formats

Dorf, Leonid A, Raitses, Yevgeny F, Smirnov, Artem N, and Fisch, Nathaniel J. Anode Fall Formation in a Hall Thruster. United States: N. p., 2004. Web. doi:10.2172/828266.
Dorf, Leonid A, Raitses, Yevgeny F, Smirnov, Artem N, & Fisch, Nathaniel J. Anode Fall Formation in a Hall Thruster. United States. https://doi.org/10.2172/828266
Dorf, Leonid A, Raitses, Yevgeny F, Smirnov, Artem N, and Fisch, Nathaniel J. 2004. "Anode Fall Formation in a Hall Thruster". United States. https://doi.org/10.2172/828266. https://www.osti.gov/servlets/purl/828266.
@article{osti_828266,
title = {Anode Fall Formation in a Hall Thruster},
author = {Dorf, Leonid A and Raitses, Yevgeny F and Smirnov, Artem N and Fisch, Nathaniel J},
abstractNote = {As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. 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. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed.},
doi = {10.2172/828266},
url = {https://www.osti.gov/biblio/828266}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jun 29 00:00:00 EDT 2004},
month = {Tue Jun 29 00:00:00 EDT 2004}
}