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Title: Tungsten impurity transport experiments in Alcator C-Mod to address high priority research and development for ITER

Experiments in Alcator C-Mod tokamak plasmas in the Enhanced D-alpha H-mode regime with ITER-like mid-radius plasma density peaking and Ion Cyclotron Resonant heating, in which tungsten is introduced by the laser blow-off technique, have demonstrated that accumulation of tungsten in the central region of the plasma does not take place in these conditions. The measurements obtained are consistent with anomalous transport dominating tungsten transport except in the central region of the plasma where tungsten transport is neoclassical, as previously observed in other devices with dominant neutral beam injection heating, such as JET and ASDEX Upgrade. In contrast to such results, however, the measured scale lengths for plasma temperature and density in the central region of these Alcator C-Mod plasmas, with density profiles relatively flat in the core region due to the lack of core fuelling, are favourable to prevent inter and intra sawtooth tungsten accumulation in this region under dominance of neoclassical transport. Simulations of ITER H-mode plasmas, including both anomalous (modelled by the Gyro-Landau-Fluid code GLF23) and neoclassical transport for main ions and tungsten and with density profiles of similar peaking to those obtained in Alcator C-Mod show that accumulation of tungsten in the central plasma region is alsomore » unlikely to occur in stationary ITER H-mode plasmas due to the low fuelling source by the neutral beam injection (injection energy ∼ 1 MeV), which is in good agreement with findings in the Alcator C-Mod experiments.« less
Authors:
; ;  [1] ;  [2] ; ; ; ; ; ;  [3] ;  [4] ; ;  [5] ;  [6]
  1. ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex (France)
  2. York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)
  3. Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
  4. Technische Universität Wien, Atominstitut, Stadionallee 2, 1020 Vienna (Austria)
  5. Max-Planck-Institut für Plasmaphysik, Boltzmanstraße 2, D-85748 Garching (Germany)
  6. NRC “Kurchatov Institute,” Kurchatov Square 1, 123098 Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
22410395
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 5; Other Information: (c) 2015 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; ALCATOR DEVICE; ASDEX TOKAMAK; BEAM INJECTION; BEAM INJECTION HEATING; ECR HEATING; ELECTRON TEMPERATURE; H-MODE PLASMA CONFINEMENT; ION TEMPERATURE; ITER TOKAMAK; JET TOKAMAK; LASERS; NEOCLASSICAL TRANSPORT THEORY; PLASMA DENSITY; PLASMA IMPURITIES; PLASMA INSTABILITY; PLASMA SIMULATION; TUNGSTEN