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Title: Nonlinear response of magnetic islands to localized electron cyclotron current injection

The magnetic island evolution under the action of a current generated externally by electron cyclotron wave beams is studied using a reduced resistive magnetohydrodynamics plasma model. The use of a two-dimensional reconnection model shows novel features of the actual nonlinear evolution as compared to the zero-dimensional model of the generalized Rutherford equation. When the radio frequency control is applied to a small magnetic island, the complete annihilation of the island width is followed by a spatial phase shift of the island, referred as “flip” instability. On the other hand, a current-drive injection in a large nonlinear island can be accompanied by the occurrence of a Kelvin-Helmholtz instability. These effects need to be taken into account in designing tearing mode control systems based on radio frequency current-drive.
Authors:
 [1] ;  [2] ; ;  [3] ;  [2] ;  [4]
  1. Dipartimento di Fisica, Università di Pisa, Pisa (Italy)
  2. (Italy)
  3. Dipartimento Energia, Politecnico di Torino, Torino (Italy)
  4. Istituto di Fisica del Plasma “P.Caldirola,” Associazione Euratom-ENEA-CNR, Milano (Italy)
Publication Date:
OSTI Identifier:
22299941
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 6; Other Information: (c) 2014 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; CONTROL SYSTEMS; DESIGN; EQUATIONS; HELMHOLTZ INSTABILITY; MAGNETIC ISLANDS; MAGNETOHYDRODYNAMICS; NONLINEAR PROBLEMS; PHASE SHIFT; PLASMA; RADIOWAVE RADIATION; TEARING INSTABILITY; TWO-DIMENSIONAL CALCULATIONS