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Title: ERO modeling and analysis of tungsten erosion and migration from a toroidally symmetric source in the DIII-D divertor

Abstract

A toroidally symmetric tungsten ring inserted in the lower outer divertor of DIII-D was exposed to 25 repeated, attached L-mode shots in reverse- B t configuration. Radial profiles of the W gross erosion flux inferred in situ from spectroscopic measurements of the WI line (400.9 nm) during these experiments are well reproduced by ERO-D3D simulations of carbon and tungsten impurity erosion, transport and redeposition in the outer divertor region. Tungsten gross erosion is mainly induced by physical sputtering of tungsten by carbon impurities. The outward radial transport of carbon impurities in the outer divertor is shown to be mainly governed by E × B drifts in the sheath region. In addition, the erosion and redeposition of carbon on tungsten, induced by the implantation of carbon into tungsten modeled with the homogeneous mixed material model, increases the effective flux of carbon impurities onto the tungsten ring (carbon recycling on tungsten). The dynamics of carbon implantation in tungsten is shown to be consistent with the plasma shot duration in DIII-D. Moreover, it is shown that the localized deposition of tungsten measured experimentally in the outboard region away from the tungsten ring is caused by the long-range radial transport of tungsten impurities inmore » the outer divertor region induced by the interplay between poloidal and radial E × B drifts. Such experimental measurements might provide direct quantitative estimations of tungsten net erosion. In conclusion, the modeling and analysis of carbon and tungsten erosion and redeposition presented in this paper demonstrates that various physical mechanisms and their synergistic effects need to be taken into account to accurately describe erosion, transport and redeposition of impurities in tokamak divertors.« less

Authors:
ORCiD logo [1];  [1];  [2];  [3];  [1];  [3]; ORCiD logo [4]; ORCiD logo [5];  [1]; ORCiD logo [1]
  1. General Atomics, San Diego, CA (United States)
  2. Auburn Univ., Auburn, AL (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Univ. of California San Diego, La Jolla, CA (United States)
  5. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1574015
Grant/Contract Number:  
FC02-04ER54698
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 60; Journal Issue: 1; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tungsten; erosion; transport; divertor

Citation Formats

Guterl, J., Abrams, T., Johnson, C. A., Jaervinen, A., Wang, H. Q., McLean, A. G., Rudakov, D., Wampler, W. R., Guo, H. Y., and Snyder, P. ERO modeling and analysis of tungsten erosion and migration from a toroidally symmetric source in the DIII-D divertor. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab4c54.
Guterl, J., Abrams, T., Johnson, C. A., Jaervinen, A., Wang, H. Q., McLean, A. G., Rudakov, D., Wampler, W. R., Guo, H. Y., & Snyder, P. ERO modeling and analysis of tungsten erosion and migration from a toroidally symmetric source in the DIII-D divertor. United States. doi:10.1088/1741-4326/ab4c54.
Guterl, J., Abrams, T., Johnson, C. A., Jaervinen, A., Wang, H. Q., McLean, A. G., Rudakov, D., Wampler, W. R., Guo, H. Y., and Snyder, P. Thu . "ERO modeling and analysis of tungsten erosion and migration from a toroidally symmetric source in the DIII-D divertor". United States. doi:10.1088/1741-4326/ab4c54.
@article{osti_1574015,
title = {ERO modeling and analysis of tungsten erosion and migration from a toroidally symmetric source in the DIII-D divertor},
author = {Guterl, J. and Abrams, T. and Johnson, C. A. and Jaervinen, A. and Wang, H. Q. and McLean, A. G. and Rudakov, D. and Wampler, W. R. and Guo, H. Y. and Snyder, P.},
abstractNote = {A toroidally symmetric tungsten ring inserted in the lower outer divertor of DIII-D was exposed to 25 repeated, attached L-mode shots in reverse-Bt configuration. Radial profiles of the W gross erosion flux inferred in situ from spectroscopic measurements of the WI line (400.9 nm) during these experiments are well reproduced by ERO-D3D simulations of carbon and tungsten impurity erosion, transport and redeposition in the outer divertor region. Tungsten gross erosion is mainly induced by physical sputtering of tungsten by carbon impurities. The outward radial transport of carbon impurities in the outer divertor is shown to be mainly governed by E × B drifts in the sheath region. In addition, the erosion and redeposition of carbon on tungsten, induced by the implantation of carbon into tungsten modeled with the homogeneous mixed material model, increases the effective flux of carbon impurities onto the tungsten ring (carbon recycling on tungsten). The dynamics of carbon implantation in tungsten is shown to be consistent with the plasma shot duration in DIII-D. Moreover, it is shown that the localized deposition of tungsten measured experimentally in the outboard region away from the tungsten ring is caused by the long-range radial transport of tungsten impurities in the outer divertor region induced by the interplay between poloidal and radial E × B drifts. Such experimental measurements might provide direct quantitative estimations of tungsten net erosion. In conclusion, the modeling and analysis of carbon and tungsten erosion and redeposition presented in this paper demonstrates that various physical mechanisms and their synergistic effects need to be taken into account to accurately describe erosion, transport and redeposition of impurities in tokamak divertors.},
doi = {10.1088/1741-4326/ab4c54},
journal = {Nuclear Fusion},
number = 1,
volume = 60,
place = {United States},
year = {2019},
month = {11}
}

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