Experimental electron temperature gradient dependence of heavy impurity transport in fusion devices.
The turbulent impurity (nickel) transport dependence on the normalized electron temperature gradient has been analyzed in sawtooth-free electron cyclotron wave heated Tore Supra plasmas. In the core, our experimental analysis shows that the lower R/L((T)(e)), the lower the nickel diffusion coefficient. The latter decreases until the instability threshold is reached. The experimental threshold is in agreement with the one computed by a gyrokinetic model. Further out, R/L((T)(e)) plays no role in the impurity diffusion. This set of experimental results is consistent with a quasilinear gyrokinetic analysis.
Villegas
D
D
CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France.
Guirlet
R
R
Bourdelle
C
C
Hoang
G T
GT
Garbet
X
X
Sabot
R
R