A Comparison between divertor heat loads in ELMy and HRS H-modes on JFT-2M

Kawashima, Hisato; Uehara, Kazuya; Nishino, Nobuhiro*; Kamiya, Kensaku; Tsuzuki, Kazuhiro; Bakhtiari, M.; Nagashima, Yoshihiko*; Ogawa, Hiroaki; Hoshino, Katsumichi; Suzuki, Sadaaki; Kusama, Yoshinori

A comparison of divertor heat load between ELMy and "High Recycling Steady" (HRS) H-mode was carried out by fast measurements of the two dimensional emission, and the divertor electron temperature and ion saturation current on JFT-2M. They brought an attractive feature of HRS H-mode that the heat load was reduced to the level on time average that for ELMy H-mode, being able to avoid the severe heat load during pulsed ELM event. It was also indicated that the HRS H-mode was dominated by an enhancement of particle transport, whereas both heat and particle transport increased abruptly at ELM event.