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Title: Development of magnetohydrodynamic modes during sawteeth in tokamak plasmas

A dynamical analysis applied to a reduced resistive magnetohydrodynamics model is shown to explain the chronology of the nonlinear destabilization of modes observed in tokamak sawteeth. A special emphasis is put on the nonlinear self-consistent perturbation of the axisymmetric m = n = 0 mode that manifests through the q-profile evolution. For the very low fusion-relevant resistivity values, the q-profile is shown to remain almost unchanged on the early nonlinear timescale within the central tokamak region, which supports a partial reconnection scenario. Within the resistive region, indications for a local flattening or even a local reversed-shear of the q-profile are given. The impact of this ingredient in the occurrence of the sawtooth crash is discussed.
Authors:
;  [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Laboratoire de Physique des Plasmas, CNRS-Ecole Polytechnique, 91128 Palaiseau cedex (France)
  2. Centro Atómico Bariloche (CNEA) and Instituto Balseiro (UNC-CNEA), San Carlos de Bariloche, RN 8400 (Argentina)
  3. (CONICET), Bariloche (Argentina)
  4. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bariloche (Argentina)
  5. Laboratoire d'Optique Appliquée, ENSTA, CNRS, Ecole Polytechnique, 91761 Palaiseau (France)
Publication Date:
OSTI Identifier:
22227942
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 7; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; AXIAL SYMMETRY; DISTURBANCES; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; NONLINEAR PROBLEMS; PLASMA; PLASMA CONFINEMENT; PLASMA INSTABILITY; PLASMA RADIAL PROFILES; REVERSED SHEAR; SAWTOOTH OSCILLATIONS; TOKAMAK DEVICES