(TH/P8-8) Influence of RF Fields on Anomalous Impurity Transport in Tokamaks

G.L.  Eriksson1), H. Nordman2), R. Singh3), T. Fülöp2), R. Dumont1), P. Kaw3), P. Strand2), M. Tokar4), J. Weiland2)
 
1) CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France.
2) Department of Radio and Space Science, Chalmers University of Technology, Euratom-VR Association, SE-412 96 Göteborg, Sweden.
3) Institute for plasma Research, Bhat, Gandhinagar-382 428, India
4) Institute for Plasma Physics, Forschungszentrum Jülich GmbH, Association FZJ-Euratom, 52425, Jülich, Germany

Abstract.  The transport of impurities by Ion-Temperature-Gradient (ITG) and Trapped-Electron (TE) mode turbulence in the presence of RF fields in the ion cyclotron range of frequencies is investigated using an electrostatic, collisionless fluid model. The trace impurity diffusivity and convective velocity (pinch) are calculated and their scaling with plasma parameters are investigated. Two separate effects of the RF field on the ITG/TE stability and transport are considered: a four wave parametric process involving a fast magnetosonic source wave and ion cyclotron sidebands; and the ponderomotive force associated with the RF field of the fast magnetosonic wave. It is found that the inward impurity convective velocity can be reduced by the RF field, in particular close to the wave resonance location where the RF ponderomotive force may be significant.

Full paper available (PDF)