Publication

Neoclassical tearing mode seeding by coupling with infernal modes in low-shear tokamaks

Jonathan Graves, Wilfred Anthony Cooper, Federico David Halpern, Daniele Brunetti, Andreas Kleiner
2016
Journal Articles

Abstract

A numerical and an analytical study of the triggering of resistive MHD modes in tokamak plasmas with low magnetic shear core is presented. Flat q profiles give rise to fast growing pressure driven MHD modes, such as infernal modes. It has been shown that infernal modes drive fast growing islands on neighbouring rational surfaces. Numerical simulations of such instabilities in a MAST-like configuration are performed with the initial value stability code XTOR-2F in the resistive frame. The evolution of magnetic islands are computed from XTOR-2F simulations and an analytical model is developed based on Rutherford's theory in combination with a model of resistive infernal modes. The parameter Delta' is extended from the linear phase to the non-linear phase. Additionally, the destabilizing contribution due to a helically perturbed bootstrap current is considered. Comparing the numerical XTOR-2F simulations to the model, we find that coupling has a strong destabilising effect on (neoclassical) tearing modes and is able to seed 2/1 magnetic islands in situations when the standard NTM theory predicts stability.

Official source

https://infoscience.epfl.ch/entities/publication/22469bc0-6816-4b99-a2ec-6f9eb8712540

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Jonathan Graves, Wilfred Anthony Cooper, Federico David Halpern, Daniele Brunetti, Andreas Kleiner
2016
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/22469bc0-6816-4b99-a2ec-6f9eb8712540

About this result

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Neoclassical tearing mode seeding by coupling with infernal modes in low-shear tokamaks

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