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Title: A Sheath Model for Negative Ion Sources Including the Formation of a Virtual Cathode

Abstract

A one dimensional model of the sheath between the plasma and the wall in a negative ion source has been developed. The plasma consists of positive ions, electrons and negative ions. The model takes into account the emission of negative ions from the wall into the sheath and thus represents the conditions in a caesiated ion source with surface production of negative ions. At high current densities of the emitted negative ions, the sheath is unable to support the transport of all the negative ions to the plasma and a virtual cathode is formed. This model takes this into account and allows the calculation of the transported negative ions across the sheath with the virtual cathode. The model has been extended to allow the linkage between plasma conditions at the sheath edge and the plasma to be made. Comparisons are made between the results of the model and experimental measurements.

Authors:
; ;  [1];  [2]
  1. EURATOM/CCFE Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom)
  2. Marcham Scientific, Hungerford, Berkshire RG17 0LH (United Kingdom)
Publication Date:
OSTI Identifier:
21611719
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1390; Journal Issue: 1; Conference: 2. international symposium on negative ions, beams and sources, Takayama City (Japan), 16-19 Nov 2010; Other Information: DOI: 10.1063/1.3637377; (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 43 PARTICLE ACCELERATORS; ANIONS; CATHODES; CATIONS; COMPARATIVE EVALUATIONS; CURRENT DENSITY; ELECTRONS; ION SOURCES; ONE-DIMENSIONAL CALCULATIONS; PLASMA; PLASMA BEAM INJECTION; PLASMA HEATING; PLASMA SHEATH; BEAM INJECTION; CHARGED PARTICLES; ELECTRODES; ELEMENTARY PARTICLES; EVALUATION; FERMIONS; HEATING; IONS; LEPTONS

Citation Formats

McAdams, R., King, D. B., Surrey, E., and Holmes, A. J. T. A Sheath Model for Negative Ion Sources Including the Formation of a Virtual Cathode. United States: N. p., 2011. Web. doi:10.1063/1.3637377.
McAdams, R., King, D. B., Surrey, E., & Holmes, A. J. T. A Sheath Model for Negative Ion Sources Including the Formation of a Virtual Cathode. United States. doi:10.1063/1.3637377.
McAdams, R., King, D. B., Surrey, E., and Holmes, A. J. T. Mon . "A Sheath Model for Negative Ion Sources Including the Formation of a Virtual Cathode". United States. doi:10.1063/1.3637377.
@article{osti_21611719,
title = {A Sheath Model for Negative Ion Sources Including the Formation of a Virtual Cathode},
author = {McAdams, R. and King, D. B. and Surrey, E. and Holmes, A. J. T.},
abstractNote = {A one dimensional model of the sheath between the plasma and the wall in a negative ion source has been developed. The plasma consists of positive ions, electrons and negative ions. The model takes into account the emission of negative ions from the wall into the sheath and thus represents the conditions in a caesiated ion source with surface production of negative ions. At high current densities of the emitted negative ions, the sheath is unable to support the transport of all the negative ions to the plasma and a virtual cathode is formed. This model takes this into account and allows the calculation of the transported negative ions across the sheath with the virtual cathode. The model has been extended to allow the linkage between plasma conditions at the sheath edge and the plasma to be made. Comparisons are made between the results of the model and experimental measurements.},
doi = {10.1063/1.3637377},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1390,
place = {United States},
year = {2011},
month = {9}
}