Pedestal characteristics of ELMy H-mode plasmas in JT-60U

Urano, Hajime; Sakamoto, Yoshiteru; Oyama, Naoyuki; Kamiya, Kensaku; Kojima, Atsushi; Hayashi, Nobuhiko; Aiba, Nobuyuki; Kamada, Yutaka; JT-60 Team

In JT-60U, the physics basis and control of the H-mode pedestal have been studied. Frequency of type-I ELMs becomes higher with increasing counter toroidal rotation. Fast recovery of density pedestal was observed after the ELM crash. ELM perturbation profile of density and temperature extends inward with co-NBI. In grassy ELM regime, ELM frequency increases with counter-toroidal rotation independently of . The amplitude of grassy ELM decreases as edge collisionality decreases. QH-mode was obtained at nearly zero or slightly co-toroidal rotation at the plasma edge. Scaling of pedestal width was examined by using hydrogen/deuterium discharges. It was found that dependence of pedestal width on the Larmor radius is weak.