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Title: Influence of magnetic shear on impurity transport

Abstract

The magnetic shear dependence of impurity transport in tokamaks is studied using a quasilinear fluid model for ion temperature gradient (ITG) and trapped electron (TE) mode driven turbulence in the collisionless limit and the results are compared with nonlinear gyrokinetic results using GYRO [J. Candy and R. E. Waltz, J. Comput. Phys 186, 545 (2003)]. It is shown that the impurity transport is sensitive to the magnetic shear, in particular for weak, negative, and large positive shear where a strong reduction of the effective impurity diffusivity is obtained. The fluid and gyrokinetic results are in qualitative agreement, with the gyrokinetic diffusivities typically a factor 2 larger than the fluid diffusivities. The steady state impurity profiles in source-free plasmas are found to be considerably less peaked than the electron density profiles for moderate shear. Comparisons between anomalous and neoclassical transport predictions are performed for ITER-like profiles [R. Aymar, P. Barabaschi, and Y. Shimomura, Plasma Phys. Controlled Fusion 44, 519 (2002)].

Authors:
; ; ; ;  [1];  [2];  [3]
  1. Department of Radio and Space Science, Chalmers University of Technology and Euratom-VR Association, Goeteborg (Sweden)
  2. (United States)
  3. (Sweden)
Publication Date:
OSTI Identifier:
20974973
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2730491; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COMPARATIVE EVALUATIONS; ELECTRON DENSITY; ELECTRON TEMPERATURE; ION TEMPERATURE; ITER TOKAMAK; NEOCLASSICAL TRANSPORT THEORY; NONLINEAR PROBLEMS; PLASMA; PLASMA CONFINEMENT; PLASMA DENSITY; PLASMA IMPURITIES; PLASMA INSTABILITY; SHEAR; TEMPERATURE GRADIENTS; TRAPPED ELECTRONS

Citation Formats

Nordman, H., Fueloep, T., Candy, J., Strand, P., Weiland, J., General Atomics, P.O. Box 85608, San Diego, California 92186-5608, and Department of Radio and Space Science, Chalmers University of Technology and Euratom-VR Association, Goeteborg. Influence of magnetic shear on impurity transport. United States: N. p., 2007. Web. doi:10.1063/1.2730491.
Nordman, H., Fueloep, T., Candy, J., Strand, P., Weiland, J., General Atomics, P.O. Box 85608, San Diego, California 92186-5608, & Department of Radio and Space Science, Chalmers University of Technology and Euratom-VR Association, Goeteborg. Influence of magnetic shear on impurity transport. United States. doi:10.1063/1.2730491.
Nordman, H., Fueloep, T., Candy, J., Strand, P., Weiland, J., General Atomics, P.O. Box 85608, San Diego, California 92186-5608, and Department of Radio and Space Science, Chalmers University of Technology and Euratom-VR Association, Goeteborg. Tue . "Influence of magnetic shear on impurity transport". United States. doi:10.1063/1.2730491.
@article{osti_20974973,
title = {Influence of magnetic shear on impurity transport},
author = {Nordman, H. and Fueloep, T. and Candy, J. and Strand, P. and Weiland, J. and General Atomics, P.O. Box 85608, San Diego, California 92186-5608 and Department of Radio and Space Science, Chalmers University of Technology and Euratom-VR Association, Goeteborg},
abstractNote = {The magnetic shear dependence of impurity transport in tokamaks is studied using a quasilinear fluid model for ion temperature gradient (ITG) and trapped electron (TE) mode driven turbulence in the collisionless limit and the results are compared with nonlinear gyrokinetic results using GYRO [J. Candy and R. E. Waltz, J. Comput. Phys 186, 545 (2003)]. It is shown that the impurity transport is sensitive to the magnetic shear, in particular for weak, negative, and large positive shear where a strong reduction of the effective impurity diffusivity is obtained. The fluid and gyrokinetic results are in qualitative agreement, with the gyrokinetic diffusivities typically a factor 2 larger than the fluid diffusivities. The steady state impurity profiles in source-free plasmas are found to be considerably less peaked than the electron density profiles for moderate shear. Comparisons between anomalous and neoclassical transport predictions are performed for ITER-like profiles [R. Aymar, P. Barabaschi, and Y. Shimomura, Plasma Phys. Controlled Fusion 44, 519 (2002)].},
doi = {10.1063/1.2730491},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}