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Title: Measurements of the deuterium ion toroidal rotation in the DIII-D tokamak and comparison to neoclassical theory

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.3694656· OSTI ID:22072385
; ;  [1];  [2];  [3];  [4]
  1. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
  2. General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
  3. University of California, Irvine, California 92697 (United States)
  4. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

Bulk ion toroidal rotation plays a critical role in controlling microturbulence and MHD stability as well as yielding important insight into angular momentum transport and the investigation of intrinsic rotation. So far, our understanding of bulk plasma flow in hydrogenic plasmas has been inferred from impurity ion velocity measurements and neoclassical theoretical calculations. However, the validity of these inferences has not been tested rigorously through direct measurement of the main-ion rotation in deuterium plasmas, particularly in regions of the plasma with steep pressure gradients where very large differences can be expected between bulk ion and impurity rotation. New advances in the analysis of wavelength-resolved D{sub {alpha}} emission on the DIII-D tokamak [J. L. Luxon et al., Fusion Sci. Technol. 48, 807 (2002)] have enabled accurate measurements of the main-ion (deuteron) temperature and toroidal rotation. The D{sub {alpha}} emission spectrum is accurately fit using a model that incorporates thermal deuterium charge exchange, beam emission, and fast ion D{sub {alpha}} (FIDA) emission spectra. Simultaneous spectral measurements of counter current injected and co current injected neutral beams permit a direct determination of the deuterium toroidal velocity. Time-dependent collisional radiative modeling of the photoemission process is in quantitative agreement with measured spectral characteristics. L-mode discharges with low beam ion densities and broad thermal pressure profiles exhibit deuteron temperature and toroidal rotation velocities similar to carbon. However, intrinsic rotation H-mode conditions and plasmas with internal transport barriers exhibit differences between core deuteron and carbon rotation which are inconsistent with the sign and magnitude of the neoclassical predictions.

OSTI ID:
22072385
Journal Information:
Physics of Plasmas, Vol. 19, Issue 5; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English