Self-consistent simulation of torque generation by radial current due to fast particles

Honda, Mitsuru; Takizuka, Tomonori; Fukuyama, Atsushi*; Yoshida, Maiko; Ozeki, Takahisa

The generation of the toroidal rotation due to the radial current torque induced by the charge separation is studied by using one-dimensional multi-fluid transport code TASK/TX. Owing to the effect of the drift motion, the charge separation occurs as long as trapped ions are generated, typically by near-perpendicular NBI. Coupling the TASK/TX code with the OFMC code, we have reproduced that the toroidal rotation is driven due to the generation of the radial current by the near-perpendicular NBI. The simulations has clarified that the NB on the equatorial plane drives the toroidal rotation most efficiently from the aspects of the collisional and torques. The torque becomes a major driver of the rotation in a high density plasma. In a steady state, the toroidal rotation is determined by the balance among the torque, the viscosity, the friction with neutrals and the loss of momentum due to charge exchange.