Influence of magnetic shear on impurity transport

Journal Article · Tue May 15 04:00:00 EDT 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2730491· OSTI ID:20974973

Nordman, H; Fueloep, T; Candy, J; Strand, P; Weiland, J ^[1]

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1. Department of Radio and Space Science, Chalmers University of Technology and Euratom-VR Association, Goeteborg (Sweden)

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)].

• OSTI ID: 20974973
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 14; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

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