A Comparison between Divertor Heat Loads in ELMy and HRS H-Modes on JFT-2M

Abstract

A comparison between divertor heat loads in ELMy and High Recycling Steady (HRS) H-modes was carried out by fast measurements of the two dimensional D_α emission, and the divertor electron temperature and ion saturation current on JFT-2M. The heat load for the HRS H-mode was maintained at the same level as the time-averaged heat load for the ELMy H-mode, indicating that the HRS H-mode has the attractive advantage of avoiding the severe ELM heat load. An enhancement of particle transport dominated the heat load for the HRS H-mode, whereas the large ELM heat load was induced by abrupt increases of both heat and particle transport.