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Title: Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region

Abstract

Despite their long history and wide range of applicability that includes electric propulsion, detailed understanding of the driving physics inside orificed hollow cathodes remains elusive. The theoretical complexity associated with the multicomponent fluid inside the cathode, and the difficulty of accessing empirically this region, have limited our ability to design cathodes that perform better and last longer. A two-dimensional axisymmetric theoretical model of the multispecies fluid inside an orificed hollow cathode is presented. The level of detail attained by the model is allowed by its extended system of governing equations not solved for in the past within the hollow cathode. Such detail is motivated in part by the need to quantify the effect(s) of the plasma on the emitter life, and by the need to build the foundation for future modeling that will assess erosion of the keeper plate. Results from numerical simulations of a 1.2-cm-diam cathode operating at a discharge current of 25 A and a gas flow rate of 5 SCCM show that approximately 10 A of electron current, and 3.45 A of ion current return back to the emitter surface. The total emitted electron current is 33.8 A and the peak emitter temperature is found to bemore » 1440 K. Comparisons with the measurements suggest that anomalous heating of the plasma is possible near the orifice region. The model predicts heavy species temperatures as high as 2034 K and peak voltage drops near the emitting surface not exceeding 8 V.« less

Authors:
; ; ;  [1]
  1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109 (United States)
Publication Date:
OSTI Identifier:
20714140
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 98; Journal Issue: 11; Other Information: DOI: 10.1063/1.2135409; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AXIAL SYMMETRY; ELECTRON EMISSION; ELECTRON TEMPERATURE; ELECTRONS; EQUATIONS; EROSION; GAS FLOW; GLOW DISCHARGES; HOLLOW CATHODES; ION TEMPERATURE; PLASMA; PLASMA HEATING; PLASMA SIMULATION; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 1000-4000 K; TWO-DIMENSIONAL CALCULATIONS; VOLTAGE DROP; WALL EFFECTS

Citation Formats

Mikellides, Ioannis G., Katz, Ira, Goebel, Dan M., and Polk, James E. Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region. United States: N. p., 2005. Web. doi:10.1063/1.2135409.
Mikellides, Ioannis G., Katz, Ira, Goebel, Dan M., & Polk, James E. Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region. United States. doi:10.1063/1.2135409.
Mikellides, Ioannis G., Katz, Ira, Goebel, Dan M., and Polk, James E. Thu . "Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region". United States. doi:10.1063/1.2135409.
@article{osti_20714140,
title = {Hollow cathode theory and experiment. II. A two-dimensional theoretical model of the emitter region},
author = {Mikellides, Ioannis G. and Katz, Ira and Goebel, Dan M. and Polk, James E.},
abstractNote = {Despite their long history and wide range of applicability that includes electric propulsion, detailed understanding of the driving physics inside orificed hollow cathodes remains elusive. The theoretical complexity associated with the multicomponent fluid inside the cathode, and the difficulty of accessing empirically this region, have limited our ability to design cathodes that perform better and last longer. A two-dimensional axisymmetric theoretical model of the multispecies fluid inside an orificed hollow cathode is presented. The level of detail attained by the model is allowed by its extended system of governing equations not solved for in the past within the hollow cathode. Such detail is motivated in part by the need to quantify the effect(s) of the plasma on the emitter life, and by the need to build the foundation for future modeling that will assess erosion of the keeper plate. Results from numerical simulations of a 1.2-cm-diam cathode operating at a discharge current of 25 A and a gas flow rate of 5 SCCM show that approximately 10 A of electron current, and 3.45 A of ion current return back to the emitter surface. The total emitted electron current is 33.8 A and the peak emitter temperature is found to be 1440 K. Comparisons with the measurements suggest that anomalous heating of the plasma is possible near the orifice region. The model predicts heavy species temperatures as high as 2034 K and peak voltage drops near the emitting surface not exceeding 8 V.},
doi = {10.1063/1.2135409},
journal = {Journal of Applied Physics},
number = 11,
volume = 98,
place = {United States},
year = {Thu Dec 01 00:00:00 EST 2005},
month = {Thu Dec 01 00:00:00 EST 2005}
}