Simulation study of density dynamics effect on the ELM behavior with TOPICS-IB

Hayashi, Nobuhiko; Takizuka, Tomonori; Aiba, Nobuyuki; Ozeki, Takahisa; Oyama, Naoyuki

Density dynamics effect on ELM has been studied by TOPICS-IB. The ELM particle loss is found to almost independent on the collisionality, as shown in experiments, due to the density profile before ELM and the increase of the SOL density during ELM. It is confirmed by varying the density and the temperature instead of artificially enhancing the collisionality that the collisionality dependence of the ELM energy loss is caused by the bootstrap current and the SOL transport. Additionally, ion convective and charge-exchange losses are found to enhance the collisionality dependence due to the equipartition effect.