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Title: Space Charge Neutralization in the ITER Negative Ion Beams

Abstract

A model of the space charge neutralization of negative ion beams, developed from the model due to Holmes, is applied to the ITER heating and diagnostic beams. The Holmes model assumed that the plasma electron temperature was derived from the stripped electrons. This is shown to be incorrect for the ITER beams and the plasma electron temperature is obtained from the average creation energy upon ionization. The model shows that both ITER beams will be fully space charge compensated in the drift distance between the accelerator and the neutralizer. Inside the neutralizer, the plasma over compensates the space charge to the extent that a significant focusing force is predicted. At a certain position in the neutraliser this force balances the defocusing force due to the ions' transverse energy. Under these conditions the beam distribution function can change from Gaussian to Bennett and evidence of such a distribution observed in a multi-aperture, neutralized negative ion beam is presented.

Authors:
 [1]
  1. EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB (United Kingdom)
Publication Date:
OSTI Identifier:
21032659
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 925; Journal Issue: 1; Conference: 11. international symposium on the production and neutralization of negative ions and beams, Santa Fe, NM (United States), 13-15 Sep 2006; Other Information: DOI: 10.1063/1.2773666; (c) 2007 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:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANIONS; APERTURES; BEAM NEUTRALIZATION; BEAM-PLASMA SYSTEMS; DISTRIBUTION FUNCTIONS; ELECTRON TEMPERATURE; ELECTRONS; ION BEAMS; ION TEMPERATURE; IONIZATION; ITER TOKAMAK; PLASMA; SPACE CHARGE; TRANSVERSE ENERGY

Citation Formats

Surrey, Elizabeth. Space Charge Neutralization in the ITER Negative Ion Beams. United States: N. p., 2007. Web. doi:10.1063/1.2773666.
Surrey, Elizabeth. Space Charge Neutralization in the ITER Negative Ion Beams. United States. https://doi.org/10.1063/1.2773666
Surrey, Elizabeth. 2007. "Space Charge Neutralization in the ITER Negative Ion Beams". United States. https://doi.org/10.1063/1.2773666.
@article{osti_21032659,
title = {Space Charge Neutralization in the ITER Negative Ion Beams},
author = {Surrey, Elizabeth},
abstractNote = {A model of the space charge neutralization of negative ion beams, developed from the model due to Holmes, is applied to the ITER heating and diagnostic beams. The Holmes model assumed that the plasma electron temperature was derived from the stripped electrons. This is shown to be incorrect for the ITER beams and the plasma electron temperature is obtained from the average creation energy upon ionization. The model shows that both ITER beams will be fully space charge compensated in the drift distance between the accelerator and the neutralizer. Inside the neutralizer, the plasma over compensates the space charge to the extent that a significant focusing force is predicted. At a certain position in the neutraliser this force balances the defocusing force due to the ions' transverse energy. Under these conditions the beam distribution function can change from Gaussian to Bennett and evidence of such a distribution observed in a multi-aperture, neutralized negative ion beam is presented.},
doi = {10.1063/1.2773666},
url = {https://www.osti.gov/biblio/21032659}, journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 925,
place = {United States},
year = {Fri Aug 10 00:00:00 EDT 2007},
month = {Fri Aug 10 00:00:00 EDT 2007}
}