Impurity transport during H-mode phase in JFT-2M

Impurity transport during the H-mode phase in JFT-2M was studied by using the spectroscopic measurement. In the quiescent H-mode (H-mode without ELM's) phase, both metal (titanium and iron) and light (carbon) impurity ions were accumulated in the plasma due to the enhanced particle confinement. From the comparison between the deuterium discharges and the hydrogen discharges, the impurity ions' accumulation was less pronounced in the hydrogen discharges due to the difference of the enhancement of the particle confinement in both discharges. In the H-mode with ELM's, impurity ions' accumulation was less pronounced compared with those in the quiescent H-mode phase. This is due to the exhaustion of the impurity ions by the ELM's. In the improved L-mode phase, impurity ion density profile became centrally-peaked which was concerned with the sawtooth oscillation. (author). 3 refs, 8 figs