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Title: Studies of RF sheaths and diagnostics on IShTAR

IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetised plasma test facility for RF sheaths studies at the Max-Planck-Institut für Plasmaphysik in Garching. In contrast to a tokamak, a test stand provides more liberty to impose the parameters and gives better access for the instrumentation and antennas. The project will support the development of diagnostic methods for characterising RF sheaths and validate and improve theoretical predictions. The cylindrical vacuum vessel has a diameter of 1 m and is 1.1 m long. The plasma is created by an external cylindrical plasma source equipped with a helical antenna that has been designed to excite the m=1 helicon mode. In inductive mode, plasma densities and electron temperatures have been characterised with a planar Langmuir probe as a function of gas pressure and input RF power. A 2D array of RF compensated Langmuir probes and a spectrometer are planned. A single strap RF antenna has been designed; the plasma-facing surface is aligned to the cylindrical plasma to ease the modelling. The probes will allow direct measurements of plasma density profiles in front of the RF antenna, and thus a detailed study of the density modifications induced by RF sheaths, which influences the coupling. The RFmore » antenna frequency has been chosen to study different plasma wave interactions: the accessible plasma density range includes an evanescent and propagative behaviour of slow or fast waves, and allows the study of the effect of the lower hybrid resonance layer.« less
Authors:
 [1] ;  [2] ; ; ; ;  [3] ; ; ; ; ;  [4] ; ; ; ;  [5] ;  [1] ;  [6]
  1. Department of Applied Physics, Ghent University, Ghent (Belgium)
  2. (Belgium)
  3. YIJL, UMR7198 CNRS-Université de Lorraine, Nancy (France)
  4. Max-Planck-Institut für Plasmaphysik, Garching (Germany)
  5. LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium)
  6. (Germany)
Publication Date:
OSTI Identifier:
22496184
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:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANTENNAS; CYCLOTRONS; CYLINDRICAL CONFIGURATION; DIAGNOSTIC TECHNIQUES; ELECTRON TEMPERATURE; FIRST WALL; ION CYCLOTRON-RESONANCE; LANGMUIR PROBE; LOWER HYBRID CURRENT DRIVE; LOWER HYBRID HEATING; PLASMA DENSITY; PLASMA WAVES; RF SYSTEMS; SIMULATION; SPECTROMETERS; TEST FACILITIES; TOKAMAK DEVICES