skip to main content

Title: Progress in controlling ICRF-edge interactions in ASDEX upgrade

RF measurements during variation of the strap voltage balance of the original 2-strap ICRF antenna in ASDEX Upgrade at constant power are consistent with electromagnetic calculations by HFSS and TOPICA, more so for the latter. RF image current compensation is observed at the antenna limiters in the experiment at a local strap voltage of about half of the value of the remote strap, albeit with a non-negligible uncertainty in phasing. The RF-specific tungsten (W) source at the broad-limiter 2-strap antenna correlates strongly with the RF voltage at the local strap at the locations not connected to opposite side of the antenna along magnetic field lines. The trends of the observed increase of the RF loading with injection of local gas are well described by a combined EMC3-Eirene – FELICE calculations, with the most efficient improvement confirmed for the outer-midplane valves, but underestimated by about 1/3. The corresponding deuterium density tailoring is also likely responsible for the decrease of local W sources observed in the experiment.
Authors:
; ; ; ; ; ; ; ; ; ; ;  [1] ; ;  [2] ; ; ;  [1] ;  [3] ; ;  [4] more »;  [5] ; « less
  1. Max-Planck-Institut für Plasmaphysik, Boltzmannstr.2, D-85748 (Germany)
  2. CCFE, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)
  3. (Belgium)
  4. CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)
  5. Institute of Plasma Physics and Laser Microfusion, Hery 23 Str., 01-497 Warsaw (Poland)
Publication Date:
OSTI Identifier:
22496182
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1689; Journal Issue: 1; Conference: 21. topical conference on radio frequency power in plasmas, Lake Arrowhead, CA (United States), 27-29 Apr 2015; Other Information: (c) 2015 EURATOM; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTENNAS; ASDEX TOKAMAK; BALANCES; DENSITY; DEUTERIUM; ELECTRIC POTENTIAL; HYPERFINE STRUCTURE; ICR HEATING; IMAGES; INJECTION; ION CYCLOTRON-RESONANCE; MAGNETIC FIELDS; RADIOWAVE RADIATION; TUNGSTEN; VALVES