|Title||Determination of the heat diffusion anisotropy by comparing measured and simulated electron temperature profiles across magnetic islands|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Authors||M. Holzl, S. Gunter, I.G.J. Classen, Q. Yu, E. Delabie|
|Type of Article||Article|
The ratio between the heat diffusion coefficients parallel and perpendicular to the magnetic field lines, chi(parallel to)/chi(perpendicular to), influences the flattening of the temperature profile inside magnetic islands and the driving term of neoclassical tearing modes (Fitzpatrick 1995 Phys. Plasmas 2 825). The value of this anisotropy is, however, not easily accessible experimentally. This paper presents a method to determine it from a systematic comparison of temperature measurements at magnetic islands with numerical heat diffusion simulations. The application of the method is demonstrated for a 2/1 magnetic island in the TEXTOR tokamak, where a heat diffusion anisotropy of 108 is observed. This is lower by a factor of 40 than predicted by Spitzer and Harm (Spitzer and Harm 1953 Phys. Rev. 89 997) and a strong indication that the heat flux limit determines the flattening of the electron temperature across magnetic islands.
|URL||<Go to ISI>://000272077800010|
|Alternate Title||Nucl. Fusion|
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