Impurity accumulation in the main plasma and radiation processes in the divetor plasma of JT-60U

Nakano, Tomohide; Kubo, Hirotaka; Asakura, Nobuyuki; Shimizu, Katsuhiro; Higashijima, Satoru

It has been found that tungsten accumulation becomes more significant with increasing plasma rotation velocity against the plasma current direction, where negative radial electric field is formed. In a high density plasma at 62% of the Greenwald density, the tungsten accumulation levels decreased significantly, suggesting a shielding effect of the peripheral plasma. It has been found that is produced by the volume recombination of and the ionization of comparably. In contrast, the volume recombination of is not detected, and the ionization flux of is less than 1% of the generation flux. Thus, this result suggests that another loss mechanism of such as transport loss from the -point is significant.