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Title: Characterization of local heat fluxes around ICRF antennas on JET

When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced power deposition on Plasma-Facing Components (PFCs) close to the antennas can occur. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat fluxes on the protection of the JET ICRF antennas, using Infra-Red (IR) thermography measurement. The measured heat flux patterns along the poloidal limiters surrounding powered antennas were compared to predictions from a simple RF sheath rectification model. The RF electric field, parallel to the static magnetic field in front of the antenna, was evaluated using the TOPICA code, integrating a 3D flattened model of the JET A2 antennas. The poloidal density variation in front of the limiters was obtained from the mapping of the Li-beam or edge reflectometry measurements using the flux surface geometry provided by EFIT equilibrium reconstruction. In many cases, this simple model can well explain the position of the maximum heat flux on the different protection limiters and the heat-flux magnitude, confirming that the parallel RF electric field and the electron plasma density in front of the antenna are the main driving parameters for ICRF-induced local heat fluxes.
Authors:
 [1] ; ; ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;
  1. Ecole Nationale des Ponts et Chaussées, F77455 Marne-la-Vallée (France)
  2. Euratom/CCFE Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)
  3. Max-Planck-Institut für Plasmaphysik, EURATOM-Assoziation, Garching (Germany)
  4. Politecnico di Torino, Department of Electronics, Torino (Italy)
  5. CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France)
Publication Date:
OSTI Identifier:
22263863
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 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTENNAS; DENSITY; DEPOSITION; ELECTRIC FIELDS; FIRST WALL; HEAT FLUX; ICR HEATING; ION CYCLOTRON-RESONANCE; IONS; ITER TOKAMAK; LIMITERS; MAGNETIC FIELDS; MAGNETIC SURFACES; PLASMA DENSITY; SAFETY