Details

Autor(en) / Beteiligte

• Cooper, W.A.
• Chapman, I.T.
• Schmitz, O.
• Turnbull, A.D.
• Tobias, B.J.
• Lazarus, E.A.
• Turco, F.
• Lanctot, M.J.
• Evans, T.E.
• Graves, J.P.
• Brunetti, D.
• Pfefferlé, D.
• Reimerdes, H.
• Sauter, O.
• Halpern, F.D.
• Tran, T.M.
• Coda, S.
• Duval, B.P.
• Labit, B.
• Pochelon, A.
• Turnyanskiy, M.R.
• Lao, L.
• Luce, T.C.
• Buttery, R.
• Ferron, J.R.
• Hollmann, E.M.
• Petty, C.C.
• van Zeeland, M.
• Fenstermacher, M.E.
• Hanson, J.M.
• Lütjens, H.

Titel

Bifurcated helical core equilibrium states in tokamaks

Ist Teil von

• Nuclear fusion, 2013-07, Vol.53 (7), p.73021-8

Ort / Verlag

IOP Publishing and International Atomic Energy Agency

Erscheinungsjahr

2013

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Tokamaks with weak to moderate reversed central shear in which the minimum inverse rotational transform (safety factor) qmin is in the neighbourhood of unity can trigger bifurcated magnetohydrodynamic equilibrium states, one of which is similar to a saturated ideal internal kink mode. Peaked prescribed pressure profiles reproduce the 'snake' structures observed in many tokamaks which has led to a novel explanation of the snake as a bifurcated equilibrium state. Snake equilibrium structures are computed in simulations of the tokamak à configuration variable (TCV), DIII-D and mega amp spherical torus (MAST) tokamaks. The internal helical deformations only weakly modulate the plasma-vacuum interface which is more sensitive to ripple and resonant magnetic perturbations. On the other hand, the external perturbations do not alter the helical core deformation in a significant manner. The confinement of fast particles in MAST simulations deteriorate with the amplitude of the helical core distortion. These three-dimensional bifurcated solutions constitute a paradigm shift that motivates the applications of tools developed for stellarator research in tokamak physics investigations.