skip to main content

Title: Nonlinear 2-D effects in the control of magnetic Islands by ECCD

The stabilization of tearing magnetic islands by means of localized current driven by electron cyclotron waves, requires optimizing the efficiency of the injected helical current. The problem is conventionally addressed using 0-D model of the (generalized) Rutherford equation to find the dependence in terms of the island width, wave beam width and deposition scale length, as well as phase tracking requirements. The use of a 2-D reconnection model shows that both the early time response of a tearing unstable system to ECCD and important nonlinear processes lead to irreversible modifications on the 2-D configuration, where 'phase' and 'width' of an island cease to be observable and controllable state variables. In particular the occurrence of a phase instability and of multiple axis and current sheets, may be a serious impediment for feedback control schemes.
Authors:
 [1] ;  [2] ; ;  [3]
  1. Istituto di Fisica del Plasma P.Caldirola, Associazione Euratom-ENEA-CNR, Milano (Italy)
  2. Dipartimento di Fisica, Università di Pisa, Pisa, Italy and Dipartimento di Energia, Politecnico di Torino, Torino (Italy)
  3. Dipartimento di Energia, Politecnico di Torino, Torino, Italy and Istituto dei Sistemi Complessi - CNR, Roma (Italy)
Publication Date:
OSTI Identifier:
22263901
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1580; Journal Issue: 1; Conference: 20. topical conference on radiofrequency power in plasmas, Sorrento (Italy), 25-28 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONTROL; ECR CURRENT DRIVE; EFFICIENCY; ELECTRONS; MAGNETIC ISLANDS