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Title: Modeling non-axisymmetry in the DIII-D small angle slot divertor using EMC3-EIRENE

Abstract

The 3D edge transport code EMC3-EIRENE is used to evaluate the effects of non-axisymmetric misalignment of the small angle slot (SAS) divertor on DIII-D. The SAS is a slot divertor with a close-fitting baffle designed to control neutral recycling to yield a wide region of low electron temperature across the divertor near the strike point and to achieve mitigated heat flux to the divertor at a lower upstream plasma density as compared to a more open geometry. The measured misalignment is simulated as an n = 1 sinusoidal offset in major radius of magnitude 5.1 mm, resulting in toroidally varying divertor conditions where local regions of high and low fluxes and a changing level of detachment can be supported. The trends can be understood in terms of the local incident angle of the magnetic field, the volume of the private flux plasma in the slot, and the energy losses along the field lines in the slot. The misaligned SAS is globally more attached and has a lower plasma density and particle flux than an axisymmetric solution. Finally, computational grids limited to the radial extent of the slot result in artificially detached solutions unless the cross-field transport coefficients are reduced suchmore » that the heat flux width is smaller than the grid width.« less

Authors:
ORCiD logo [1];  [2];  [3];  [3];  [3];  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Toronto, ON (Canada)
  3. General Atomics, San Diego, CA (United States)
  4. Univ. of Wisconsin, Madison, WI (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1479819
Alternate Identifier(s):
OSTI ID: 1488714
Grant/Contract Number:  
AC05-00OR22725; FC02-04ER54698
Resource Type:
Journal Article: Published Article
Journal Name:
Nuclear Materials and Energy
Additional Journal Information:
Journal Volume: 17; Journal Issue: C; Journal ID: ISSN 2352-1791
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY

Citation Formats

Lore, Jeremy D., Stangeby, P. C., Guo, H. Y., Covele, Brent, Moser, Auna, and Frerichs, Heinke. Modeling non-axisymmetry in the DIII-D small angle slot divertor using EMC3-EIRENE. United States: N. p., 2018. Web. doi:10.1016/j.nme.2018.10.006.
Lore, Jeremy D., Stangeby, P. C., Guo, H. Y., Covele, Brent, Moser, Auna, & Frerichs, Heinke. Modeling non-axisymmetry in the DIII-D small angle slot divertor using EMC3-EIRENE. United States. doi:10.1016/j.nme.2018.10.006.
Lore, Jeremy D., Stangeby, P. C., Guo, H. Y., Covele, Brent, Moser, Auna, and Frerichs, Heinke. Tue . "Modeling non-axisymmetry in the DIII-D small angle slot divertor using EMC3-EIRENE". United States. doi:10.1016/j.nme.2018.10.006.
@article{osti_1479819,
title = {Modeling non-axisymmetry in the DIII-D small angle slot divertor using EMC3-EIRENE},
author = {Lore, Jeremy D. and Stangeby, P. C. and Guo, H. Y. and Covele, Brent and Moser, Auna and Frerichs, Heinke},
abstractNote = {The 3D edge transport code EMC3-EIRENE is used to evaluate the effects of non-axisymmetric misalignment of the small angle slot (SAS) divertor on DIII-D. The SAS is a slot divertor with a close-fitting baffle designed to control neutral recycling to yield a wide region of low electron temperature across the divertor near the strike point and to achieve mitigated heat flux to the divertor at a lower upstream plasma density as compared to a more open geometry. The measured misalignment is simulated as an n = 1 sinusoidal offset in major radius of magnitude 5.1 mm, resulting in toroidally varying divertor conditions where local regions of high and low fluxes and a changing level of detachment can be supported. The trends can be understood in terms of the local incident angle of the magnetic field, the volume of the private flux plasma in the slot, and the energy losses along the field lines in the slot. The misaligned SAS is globally more attached and has a lower plasma density and particle flux than an axisymmetric solution. Finally, computational grids limited to the radial extent of the slot result in artificially detached solutions unless the cross-field transport coefficients are reduced such that the heat flux width is smaller than the grid width.},
doi = {10.1016/j.nme.2018.10.006},
journal = {Nuclear Materials and Energy},
issn = {2352-1791},
number = C,
volume = 17,
place = {United States},
year = {2018},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.nme.2018.10.006

Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Figures / Tables:

Fig. 1. Fig. 1.: a) Geometry of the SAS used and poloidal flux contours, b) incident angle of the magnetic field lines on the surface, c) cuts at 90° and −90° showing the minimum and maximum major radial simulated PFC offset. Red regions indicate poloidal magnetic shadowing. (For interpretation of the referencesmore » to colour in this figure legend, the reader is referred to the web version of this article.)« less

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.