Computation of generalised magnetic coordinates asymptotically close to the separatrix

2025/03/06 by Benjamin, Stuart, Logan, Nikolas, Hansen, Christopher · 1 citation
#FOS: Physical sciences #Plasma Physics (physics.plasm-ph)

paper · doi:10.48550/arxiv.2503.04934

Abstract

Integrals to calculate generalised magnetic coordinates from an input magnetic flux function asymptotically close to the separatrix are presented, and implemented in the GPEC/DCON code suite. These integrals allow characterisation of the magnetic equilibrium of a diverted tokamak, in magnetic coordinates, arbitrarily close to the last closed flux surface, avoiding the numerical issues associated with calculating diverging field line integrals near a magnetic x-point. These methods provide an important first step in the development of robust asymptotic equilibrium behaviour for spectral 3D MHD codes at the separatrix.

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• Response of a magnetically diverted tokamak plasma to a resonant magnetic perturbation

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