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Title: Modeling ExB drift transport in conceptual slot divertor configurations

Abstract

At DIII-D, a slot divertor concept, called small-angle-slot (SAS), is under development, aiming to enable detachment at relatively low plasma edge density. We report on simulations using the SOLPS-ITER two-dimensional edge code to examine the performance of conceptual “SAS 2” slot configurations. The focus of the analysis is on E × B drift effects on upstream density at detachment (UDD), with detachment marked by electron temperature Te ≤ 3 eV at the outer strike point (OSP). With toroidal field such that radial E × B drift carries particles from the OSP towards the private flux region (PFR), placing the OSP near the inner slot wall gives ≈20% lower UDD than having the OSP near the outer wall. The inner wall effectively traps the radial E × B drift flux, resulting in low Te and associated radial electric field in the PFR, and thus small losses from the slot to the inner target via poloidal E × B drift flux. With toroidal field reversed such that radial E × B drift is reversed, OSP placement near the inner wall gives ≈10% lower UDD than OSP placement near the outer wall. Although radial E × B flux is from the OSP towardsmore » the outer wall, this flux largely escapes the slot, raising the UDD. Finally, a change in the slot shaping is suggested with the goal of eliminating such E × B-driven particle losses from the slot.« less

Authors:
 [1];  [2];  [2];  [2];  [2]
  1. Univ. of Washington, Seattle, WA (United States)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
Research Org.:
Univ. of Washington, Seattle, WA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Technology Utilization (EE-34); USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1601921
Alternate Identifier(s):
OSTI ID: 1599915
Grant/Contract Number:  
SC0019473; FC02-04ER54698
Resource Type:
Accepted Manuscript
Journal Name:
Contributions to Plasma Physics
Additional Journal Information:
Journal Volume: 60; Journal Issue: 5-6; Conference: Plasma Edge Theory Workshop, San Diego, CA (United States), Aug. 19-21, 2019; Journal ID: ISSN 0863-1042
Publisher:
Wiley
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS; tokamak; divertor; plasma physics; modeling; detachment; DIII-D; ExB drifts; SAS 2 slot divertor; SOLPS-ITER

Citation Formats

Meier, E. T., Covele, B. M., Guo, H. Y., Leonard, A. W., and Thomas, D. M. Modeling ExB drift transport in conceptual slot divertor configurations. United States: N. p., 2020. Web. https://doi.org/10.1002/ctpp.201900151.
Meier, E. T., Covele, B. M., Guo, H. Y., Leonard, A. W., & Thomas, D. M. Modeling ExB drift transport in conceptual slot divertor configurations. United States. https://doi.org/10.1002/ctpp.201900151
Meier, E. T., Covele, B. M., Guo, H. Y., Leonard, A. W., and Thomas, D. M. Sat . "Modeling ExB drift transport in conceptual slot divertor configurations". United States. https://doi.org/10.1002/ctpp.201900151. https://www.osti.gov/servlets/purl/1601921.
@article{osti_1601921,
title = {Modeling ExB drift transport in conceptual slot divertor configurations},
author = {Meier, E. T. and Covele, B. M. and Guo, H. Y. and Leonard, A. W. and Thomas, D. M.},
abstractNote = {At DIII-D, a slot divertor concept, called small-angle-slot (SAS), is under development, aiming to enable detachment at relatively low plasma edge density. We report on simulations using the SOLPS-ITER two-dimensional edge code to examine the performance of conceptual “SAS 2” slot configurations. The focus of the analysis is on E × B drift effects on upstream density at detachment (UDD), with detachment marked by electron temperature Te ≤ 3 eV at the outer strike point (OSP). With toroidal field such that radial E × B drift carries particles from the OSP towards the private flux region (PFR), placing the OSP near the inner slot wall gives ≈20% lower UDD than having the OSP near the outer wall. The inner wall effectively traps the radial E × B drift flux, resulting in low Te and associated radial electric field in the PFR, and thus small losses from the slot to the inner target via poloidal E × B drift flux. With toroidal field reversed such that radial E × B drift is reversed, OSP placement near the inner wall gives ≈10% lower UDD than OSP placement near the outer wall. Although radial E × B flux is from the OSP towards the outer wall, this flux largely escapes the slot, raising the UDD. Finally, a change in the slot shaping is suggested with the goal of eliminating such E × B-driven particle losses from the slot.},
doi = {10.1002/ctpp.201900151},
journal = {Contributions to Plasma Physics},
number = 5-6,
volume = 60,
place = {United States},
year = {2020},
month = {2}
}

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