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arXiv · 1702.00076

Effect of Scrape-Off-Layer Current on Reconstructed Tokamak Equilibrium

J. R. King·S. E. Kruger·R. J. Groebner·J. D. Hanson·J. D. Hebert·E. D. Held·J. R. Jepson
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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 $\chi$-squared goodness-of-fit parameter is calculated for cases with and without scrape-off-layer current. The change in $\chi$-squared is found to be minor when scrape-off-layer current is included however flux surfaces are shifted by up to 3 cm. 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.

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J. R. King, S. E. Kruger, R. J. Groebner, J. D. Hanson, J. D. Hebert, E. D. Held, J. R. Jepson. 2017-01-31. Effect of Scrape-Off-Layer Current on Reconstructed Tokamak Equilibrium. https://doi.org/10.1063/1.4972822

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