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Title: Effect of scrape-off-layer current on reconstructed tokamak equilibrium

Abstract

Methods are described that extend fields from reconstructed equilibria to include scrape-off-layer current through extrapolated parametrized and experimental fits. The extrapolation includes both the effects of the toroidal-field and pressure gradients which produce scrape-off-layer current after recomputation of the Grad-Shafranov solution. To quantify the degree that inclusion of scrape-off-layer current modifies the equilibrium, the χ-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in χ-squared is found to be minor when scrape-off-layer current is included however flux surfaces are shifted by up to 3 cm. Here the impact on edge modes of these scrape-off-layer modifications is also found to be small and the importance of these methods to nonlinear computation is discussed.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2];  [3];  [3];  [4]; ORCiD logo [4]
  1. Tech-X Corp., Boulder, CO (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Auburn Univ., Auburn, AL (United States)
  4. Utah State Univ., Logan, UT (United States)
Publication Date:
Research Org.:
Tech-X Corp., Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Contributing Org.:
General Atomics, San Diego, CA; Auburn University, Auburn, AL; Utah State University, Logan, UT
OSTI Identifier:
1339429
Alternate Identifier(s):
OSTI ID: 1361709
Grant/Contract Number:  
FC02-08ER54972; AC02-05CH11231; FC02-04ER54698; FC02-06ER54875; FG02-03ER54692
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 1; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Grad-Shafranov equilibrium; scrape-off-layer; macroscopic stability; peeling-balooning modes

Citation Formats

King, J. R., Kruger, S. E., Groebner, R. J., Hanson, J. D., Hebert, J. D., Held, E. D., and Jepson, J. R. Effect of scrape-off-layer current on reconstructed tokamak equilibrium. United States: N. p., 2017. Web. doi:10.1063/1.4972822.
King, J. R., Kruger, S. E., Groebner, R. J., Hanson, J. D., Hebert, J. D., Held, E. D., & Jepson, J. R. Effect of scrape-off-layer current on reconstructed tokamak equilibrium. United States. doi:10.1063/1.4972822.
King, J. R., Kruger, S. E., Groebner, R. J., Hanson, J. D., Hebert, J. D., Held, E. D., and Jepson, J. R. Fri . "Effect of scrape-off-layer current on reconstructed tokamak equilibrium". United States. doi:10.1063/1.4972822. https://www.osti.gov/servlets/purl/1339429.
@article{osti_1339429,
title = {Effect of scrape-off-layer current on reconstructed tokamak equilibrium},
author = {King, J. R. and Kruger, S. E. and Groebner, R. J. and Hanson, J. D. and Hebert, J. D. and Held, E. D. and Jepson, J. R.},
abstractNote = {Methods are described that extend fields from reconstructed equilibria to include scrape-off-layer current through extrapolated parametrized and experimental fits. The extrapolation includes both the effects of the toroidal-field and pressure gradients which produce scrape-off-layer current after recomputation of the Grad-Shafranov solution. To quantify the degree that inclusion of scrape-off-layer current modifies the equilibrium, the χ-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in χ-squared is found to be minor when scrape-off-layer current is included however flux surfaces are shifted by up to 3 cm. Here the impact on edge modes of these scrape-off-layer modifications is also found to be small and the importance of these methods to nonlinear computation is discussed.},
doi = {10.1063/1.4972822},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 1,
volume = 24,
place = {United States},
year = {2017},
month = {1}
}

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