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Title: Analysis of noble gas recycling at a fusion plasma divertor

Abstract

Near-surface recycling of neon and argon atoms and ions at a divertor has been studied using impurity transport and surface interaction codes. A fixed background deuterium{endash}tritium plasma model is used corresponding to the International Thermonuclear Experimental Reactor (ITER) [{ital ITER} {ital EDA} {ital Agreement} {ital and} {ital Protocol} 2, ITER EDA Documentation Series No. 5 (International Atomic Energy Agency, Vienna, 1994)] radiative plasma conditions ({ital T}{sub {ital e}}{le}10 eV). The noble gas transport depends critically on the divertor surface material. For low-{ital Z} materials (Be and C) both neon and argon recycle many (e.g., {approximately}100) times before leaving the near-surface region. This is also true for an argon on tungsten combination. For neon on tungsten, however, there is low recycling. These variations are due to differences in particle and energy reflection coefficients, mass, and ionization rates. In some cases a high flux of recycling atoms is ionized within the magnetic sheath and this can change local sheath parameters. Due to inhibited backflow, high recycling, and possibly high sputtering, noble gas seeding (for purposes of enhancing radiation) may be incompatible with Be or C surfaces, for fusion reactor conditions. On the other hand, neon use appears compatible with tungsten. {copyright} {italmore » 1996 American Institute of Physics.}« less

Authors:
 [1]
  1. Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
Publication Date:
OSTI Identifier:
284292
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 3; Journal Issue: 6; Other Information: PBD: Jun 1996
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; ITER TOKAMAK; PLASMA IMPURITIES; RARE GASES; NEON; ARGON; DIVERTORS; DEUTERIUM; TRITIUM; BERYLLIUM; CARBON; TUNGSTEN; THERMONUCLEAR DEVICES; PLASMA SCRAPE-OFF LAYER

Citation Formats

Brooks, J N. Analysis of noble gas recycling at a fusion plasma divertor. United States: N. p., 1996. Web. doi:10.1063/1.871911.
Brooks, J N. Analysis of noble gas recycling at a fusion plasma divertor. United States. doi:10.1063/1.871911.
Brooks, J N. Sat . "Analysis of noble gas recycling at a fusion plasma divertor". United States. doi:10.1063/1.871911.
@article{osti_284292,
title = {Analysis of noble gas recycling at a fusion plasma divertor},
author = {Brooks, J N},
abstractNote = {Near-surface recycling of neon and argon atoms and ions at a divertor has been studied using impurity transport and surface interaction codes. A fixed background deuterium{endash}tritium plasma model is used corresponding to the International Thermonuclear Experimental Reactor (ITER) [{ital ITER} {ital EDA} {ital Agreement} {ital and} {ital Protocol} 2, ITER EDA Documentation Series No. 5 (International Atomic Energy Agency, Vienna, 1994)] radiative plasma conditions ({ital T}{sub {ital e}}{le}10 eV). The noble gas transport depends critically on the divertor surface material. For low-{ital Z} materials (Be and C) both neon and argon recycle many (e.g., {approximately}100) times before leaving the near-surface region. This is also true for an argon on tungsten combination. For neon on tungsten, however, there is low recycling. These variations are due to differences in particle and energy reflection coefficients, mass, and ionization rates. In some cases a high flux of recycling atoms is ionized within the magnetic sheath and this can change local sheath parameters. Due to inhibited backflow, high recycling, and possibly high sputtering, noble gas seeding (for purposes of enhancing radiation) may be incompatible with Be or C surfaces, for fusion reactor conditions. On the other hand, neon use appears compatible with tungsten. {copyright} {ital 1996 American Institute of Physics.}},
doi = {10.1063/1.871911},
journal = {Physics of Plasmas},
number = 6,
volume = 3,
place = {United States},
year = {1996},
month = {6}
}