Physical Sciences and Mathematics Commons^™

Effect Of Scrape-Off-Layer Current On Reconstructed Tokamak Equilibrium, J. R. King, Scott E. Kruger, Richard J. Groebner, James D. Hanson, J. D. Hebert, Eric D. Held, J. R. Jepson

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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 cm3 cm. The impact on edge modes of these scrape-off-layer modifications is …