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Title: Electron cyclotron heating and core intrinsic rotation reversal in DIII-D

The effect of electron cyclotron heating (ECH) on the intrinsic rotation profile in DIII-D is shown experimentally. Former DIII-D experiments have shown that ECH tends to cause an interior reduction in the normally co-Ip directed intrinsic rotation profile, and this core rotation can be fully reversed to the opposite direction. This effect is due to a turbulent rearrangement of the interior rotation profile. Here, we show results that there is more than one mechanism causing this. We compare two low density L-mode discharges where the only operational difference is the location of the ECH deposition. At low ECH power, comparable to the Ohmic power, the primary change is in the q-profile accompanied by a reversal of the core intrinsic rotation direction for the more off-axis deposition. The change in the shear of the q-profile fits well with a recent theoretical prediction for this rotation reversal. At higher ECH power, the primary change is in the core electron temperature, Te, accompanied by a hollowing of the rotation profile near the magnetic axis. This effect appears to be due to the change in electron collisionality, consistent with another theoretical, gyrokinetic prediction. The variety of phenomena that could allow ECH to modify themore » intrinsic rotation profile give some expectation that regions of large velocity shear in the interior could be generated, with the possibility of triggering internal transport barriers.« less
Authors:
 [1] ;  [2] ;  [3]
  1. General Atomics, PO Box 85608, San Diego, CA 92186-5608 (United States)
  2. University of California, San Diego, San Diego, CA 94550 (United States)
  3. Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States)
Publication Date:
OSTI Identifier:
22496224
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 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; COMPARATIVE EVALUATIONS; DENSITY; DEPOSITION; DOUBLET-3 DEVICE; ECR HEATING; ELECTRON TEMPERATURE; FORECASTING; JOULE HEATING; L-MODE PLASMA CONFINEMENT; REDUCTION; ROTATION; SHEAR; VELOCITY