UKAEA Papers

"Perturbative 3D Ideal MHD Stability of Tokamak Plasmas"

• M.S. Anastopoulos-Tzanis
• B.D. Dusdson
• C.J. Ham
• C.C. Hegna
• P.B. Snyder
• H.R. Wilson

"Non-Axisymmetric Equilibrium and Stability using the ELITE Stability Code"

• M.S. Anastopoulos-Tzanis
• B.D. Dudson
• C.J. Ham
• C.C. Hegna
• P.B. Snyder
• H.R. Wilson

A linear perturbation theory is used to model the MHD stability of tokamak equilibria under the application of external 3D magnetic perturbations [C.C. Hegna, Physics of Plasmas 21 :072502, 2014]. The symmetry breaking produces the coupling of toroidal n modes. We use ELITE [H.R. Wilson et al., Physics of Plasmas 9 :1277, 2002] to produ…

"Dynamics of ideal modes and subsequent ELM-crashes in 3D tokamak geometry from external magnetic perturbations"

• M. Willensdorfer
• T.B. Cote
• M. Griener
• D.A. Ryan
• E. Strumberger
• W. Suttrop
• N. Wang
• M. Cavedon
• S.S. Denk
• M. Dunne
• R. Fischer
• J. Galdon-Quiroga
• C.J. Ham
• C.C. Hegna
• M. Hoelzl
• A. Kirk
• M. Maraschek
• F. Mink
• N. Leuthold
• F. Orain
• E. P. Seliunin
• H. Zohm
• the ASDEX Upgrade Team
• and the MST1 Team

The impact of the three-dimensional (3D) tokamak geometry from external magnetic perturbations (MPs) on the local edge stability has been examined in high confinement mode (H-mode) plasmas with edge localised modes (ELMs) in ASDEX Upgrade. The 3D geometry has been probed using rigidly rotating MP fields. The measured distortions of the plasma bound…

"A One-Dimensional Tearing Mode Equation for ELM Studies in Tokamaks."

• JW Connor
• RJ Hastie
• C Marchetto
• CM Roach

Starting from expressions in Connor et al. (1988), we derive a one-dimensional tearing equation similar to the approximate equation obtained by Hegna & Callen (1994); Nishimura et al. (1998), but for more realistic toroidal equilibria. The intention is to use this approximation to explore the role of steep H-mode pedestals, bootstrap currents a…

"Toroidal coupling of ideal magnetohydrodynamic instabilities in tokamak plasmas"

• C. C. Hegna
• J. W. Connor
• R. J. Hastie
• H. R. Wilson

"Threshold for neoclassical magnetic islands in a low collision frequency tokamak"

• H. R. Wilson
• J. W. Connor
• R. J. Hastie
• C. C. Hegna

A kinetic theory for magnetic islands in a low collision frequency tokamak plasma is presented. Self-consistent equations for the islands’ width, w , and propagation frequency, w , are derived. These include contributions from the perturbed bootstrap current and the toroidally enhanced ion polarization drift. The bootstrap current is ind…