TITLE

Heat diffusion across magnetic islands and ergodized plasma regions in realistic tokamak geometry

AUTHOR(S)
Hölzl, M.; Günter, S.; ASDEX Upgrade Team
PUB. DATE
July 2008
SOURCE
Physics of Plasmas;Jul2008, Vol. 15 Issue 7, p072514
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Heat diffusion in magnetized plasmas is investigated numerically for tokamak geometry and realistic plasma parameters. Heat transport across single and overlapping magnetic islands is studied. As an application, the influence of an (n+1,m+1) helical perturbation onto the temperature perturbation caused by an (n,m) neoclassical tearing mode is examined. It is shown that the resulting ergodization of the magnetic field structure is able to reduce the resonant bootstrap current perturbation of a neoclassical tearing mode. This might explain the drop in the mode amplitude observed in the frequently interrupted regime. Furthermore, the influence of edge ergodization as generated by external perturbation coils onto the electron temperature is studied. It is shown that ergodization of the plasma boundary can decrease the pedestal temperature gradient significantly. This effect might be one element in the mitigation effects of edge-localized modes achieved by external resonant perturbation fields.
ACCESSION #
34360759

 

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