High-m kink/tearing modes in cylindrical geometry
Journal article, 2014

The global ideal kink equation, for cylindrical geometry and zero beta, is simplified in the high poloidal mode number limit and used to determine the tearing stability parameter, Δ'. In the presence of a steep monotonic current gradient, Δ' becomes a function of a parameter, σ0, characterising the ratio of the maximum current gradient to magnetic shear and xs, characterising the separation of the resonant surface from the maximum of the current gradient. In equilibria containing a current 'spike', so that there is a non-monotonic current profile, Δ' also depends on two parameters: κ, related to the ratio of the curvature of the current density at its maximum to the magnetic shear and xs, which now represents the separation of the resonance from the point of maximum current density. The relation of our results to earlier studies of tearing modes and to recent gyrokinetic calculations of current driven instabilities, is discussed, together with potential implications for the stability of the tokamak pedestal.

ideal kink

gyrokinetic simulation

tokamak

global description

current driven instabilities

tearing mode

Author

J W Connor

Culham Lab

Imperial College London

University of Oxford

R.J. Hastie

University of Oxford

Culham Lab

Istvan Pusztai

Chalmers, Applied Physics, Nuclear Engineering

P. J. Catto

University of Oxford

Massachusetts Institute of Technology (MIT)

M Barnes

Culham Lab

University of Oxford

The University of Texas at Austin

Plasma Physics and Controlled Fusion

0741-3335 (ISSN) 1361-6587 (eISSN)

Vol. 56 12 125006-

Areas of Advance

Energy

Subject Categories

Fusion, Plasma and Space Physics

DOI

10.1088/0741-3335/56/12/125006

More information

Latest update

4/20/2018