MHD limits in non-inductive tokamak plasmas: simulations and comparison to experiments on Tore Supra
| Autor: | P. Maget, H. Lütjens, G. Huysmans, M. Ottaviani, X. Garbet, Ph. Moreau, J.-L. Ségui, Olivier Sauter, Xavier Garbet, Elio Sindoni |
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| Přispěvatelé: | Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de Physique Théorique [Palaiseau] (CPHT), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Centre de Recherches en Physique des Plasmas (CRPP), Ecole Polytechnique Fédérale de Lausanne (EPFL), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2008 |
| Předmět: |
Physics
Jet (fluid) Safety factor Tokamak 020206 networking & telecommunications 02 engineering and technology Mechanics Tore Supra Instability law.invention [PHYS.PHYS.PHYS-COMP-PH]Physics [physics]/Physics [physics]/Computational Physics [physics.comp-ph] Amplitude [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] law 0202 electrical engineering electronic engineering information engineering 020201 artificial intelligence & image processing Atomic physics Magnetohydrodynamics ComputingMilieux_MISCELLANEOUS Linear stability |
| Zdroj: | AIP Conference Proceedings AIP Conference Proceedings, American Institute of Physics, 2008, pp.153-164. ⟨10.1063/1.3033698⟩ AIP Conference Proceedings, 2008, pp.153-164. ⟨10.1063/1.3033698⟩ |
| ISSN: | 0094-243X 1551-7616 |
| Popis: | Non‐inductive tokamak discharges with a flat or hollow current profile are prone to the triggering of large tearing modes when the minimum of the safety factor is just below a low order rational. This issue is of particular importance for discussing the optimal safety factor for MHD modes avoidance in Steady‐State reactor plasmas. Different non‐linear regimes of such magnetic configurations in Tore Supra are studied using the full MHD code XTOR [1]. Numerical simulations show that the non‐linear stage of the Double‐Tearing Mode (DTM) is governed by the full reconnection model, but a single tearing mode in a low magnetic shear configuration can have a similar impact on the confinement. The different regimes observed experimentally are recovered in the simulations: a small amplitude (2,1) DTM for close resonant surfaces as seen in Tore Supra [2], a sawtooth‐like behaviour of the (2,1) Double‐Tearing Mode as first seen in TFTR [3], or a large amplitude (2,1) tearing mode that severely degrades the energy confinement, as reported in Tore Supra [4], JET [5] or DIII‐D [6]. Situations where qmin≈1.5 with a stable n = 1 mode, as seen in Tore Supra longest discharges, seem to put specific constraints on the MHD model that is used. Indeed, curvature stabilisation without transport terms as derived in [7] could explain linear stability, but such effect vanishes in presence of heat transport [8]. Electron diamagnetic rotation effect is investigated as a possible mechanism for n = 1 mode stabilization. |
| Databáze: | OpenAIRE |
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