Kinetic effect of thermal force on impurity transport; Simulation of JT-60SA divertor with integrated divertor code SONIC

Shimizu, Katsuhiro; Takizuka, Tomonori; Kawashima, Hisato

The divertor plasma should be cooled significantly by impurities to reduce the heat load onto the divertor plate up to the permissible level in fusion reactor. To achieve enhanced radiation, the control method for impurity retention in the divertor region should be established. Aiming at this impurity control, we have investigated the impurity generation and transport. 2D multi-fluid divertor codes have been developed, where the impurity transport is solved as fluid species. On the other hand, we have developed a impurity transport modelling IMPMC based on Monte-Carlo techniques. The MC approach provides the modelling method to take into account the kinetic effect and the complex dissociation processes of hydrocarbons. Using the IMPMC, the kinetic effect of thermal force on He transport is investigated for JT-60SA detached plasma. Without the recycling process, the kinetic effect of the thermal force is found to increase the He density in the divertor region by a factor of 2, compared with the conventional (fluid) evaluation. However, the kinetic effect is masked by the recycling at the target plates.