Effects of the equilibrium model on impurity transport in tokamaks
Journal article, 2014

Gyrokinetic simulations of ion temperature gradient mode and trapped electron mode driven impurity transport in a realistic tokamak geometry are presented and compared with results using simplified geometries. The gyrokinetic results, obtained with the GENE code in both linear and non-linear modes are compared with data and analysis for a dedicated impurity injection discharge at JET. The impact of several factors on heat and particle transport is discussed, lending special focus to tokamak geometry and rotational shear. To this end, results using s–α and concentric circular equilibria are compared with results with magnetic geometry from a JET experiment. To further approach experimental conditions, non-linear gyrokinetic simulations are performed with collisions and a carbon background included. The impurity peaking factors, computed by finding local density gradients corresponding to zero particle flux, are discussed. The impurity peaking factors are seen to be reduced by a factor of ~2 in realistic geometry compared with the simplified geometries, due to a reduction of the convective pinch. It is also seen that collisions reduce the peaking factor for low-Z impurities, while increasing it for high charge numbers, which is attributed to a shift in the transport spectra towards higher wavenumbers with the addition of collisions. With the addition of roto-diffusion, an overall reduction of the peaking factors is observed, but this decrease is not sufficient to explain the flat carbon profiles seen at JET.

Transport properties

Tokamaks

Gyrofluid and gyrokinetic simulations

Nonlinear phenomena

Impurities in plasmas

Plasma devices

Author

Andreas Skyman

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Luis Fazendeiro

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Daniel Tegnered

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Hans Nordman

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Johan Anderson

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Pär Strand

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Nuclear Fusion

0029-5515 (ISSN)

Vol. 54 1 013009- 013009

Driving Forces

Sustainable development

Areas of Advance

Transport

Energy

Roots

Basic sciences

Infrastructure

C3SE (Chalmers Centre for Computational Science and Engineering)

Subject Categories

Other Physics Topics

Fusion, Plasma and Space Physics

DOI

10.1088/0029-5515/54/1/013009

More information

Created

10/6/2017