Effect of thermoelectric current splitting on the magnetic topology in DIII-D

Wingen, A.; Evans, T. E.; Spatschek, K. H.
April 2011
Physics of Plasmas;Apr2011, Vol. 18 Issue 4, p042501
Academic Journal
An extended model is proposed to describe the magnetic topology during appearance of edge localized modes (ELMs). It is applied to an ELMing H-mode in a lower single null discharge at DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)]. The process of flux tube formation is discussed based on a previously proposed two-step model. Large currents, as found in measurements in DIII-D, are assumed running through newly formed large flux tubes. Two different realizations of the current distribution within the tubes are compared, namely a single filament in each tube and a scenario where the current in each tube is split into subfilaments. The latter scenario is shown to be the more realistic distribution because it leads to much better agreement with infrared camera observations. It is demonstrated that stripe patterns in the divertor heat flux produced by an ELM in the DIII-D tokamak can be reproduced numerically by taking into account the magnetic perturbation caused by the thermoelectric current subfilaments.


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