Accumulation process of high-Z impurity in toroidal rotating tokamak plasma

Hoshino, Kazuo; Takizuka, Tomonori; Nakano, Tomohide

The accumulation process of high-Z impurity in toroidal rotating tokamak plasma is investigated. A new inward pinch of high-Z impurity due to the ionization/recombination processes is derived using an analytical model. This inward pinch is driven by the large deviation of a drift orbit from a magnetic surface and the resultant variation of the charge state along the drift orbit. The pinch velocity increases with increasing toroidal rotation speed in both the co- direction and the ctr-direction. The inward pinch expected by the analytical model is really observed in the numerical simulation using the IMPGYRO code.