Fluid and gyrokinetic simulations of impurity transport at JET

H Nordman, A Skyman, P Strand, C Giroud, F Jenko, F Merz, Volker Naulin, T Tala

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    Impurity transport coefficients due to ion-temperature-gradient (ITG) mode and trapped-electron mode turbulence are calculated using profile data from dedicated impurity injection experiments at JET. Results obtained with a multi-fluid model are compared with quasi-linear and nonlinear gyrokinetic simulation results obtained with the code GENE. The sign of the impurity convective velocity (pinch) and its various contributions are discussed. The dependence of the impurity transport coefficients and impurity peaking factor −∇nZ/nZ on plasma parameters such as impurity charge number Z, ion logarithmic temperature gradient, collisionality, E × B shearing, and charge fraction are investigated. It is found that for the studied ITG dominated JET discharges, both the fluid and gyrokinetic results show an increase in the impurity peaking factor for low Z-values followed by a saturation at moderate values of impurity peaking, much below the neoclassical predictions, for large values of Z. The results are in qualitative agreement with the experimental trends observed for the injected impurities (Ne, Ar, Ni) whereas for the background carbon species the observed flat or weakly hollow C profiles are not well reproduced by the simulations.
    Original languageEnglish
    JournalPlasma Physics and Controlled Fusion
    Volume53
    Issue number10
    Pages (from-to)105005
    ISSN0741-3335
    DOIs
    Publication statusPublished - 2011

    Keywords

    • Fusion energy

    Cite this

    Nordman, H., Skyman, A., Strand, P., Giroud, C., Jenko, F., Merz, F., Naulin, V., & Tala, T. (2011). Fluid and gyrokinetic simulations of impurity transport at JET. Plasma Physics and Controlled Fusion, 53(10), 105005. https://doi.org/10.1088/0741-3335/53/10/105005