Changes in the ELM characteristics by edge electron cyclotron wave injection

Oyama, Naoyuki; Yoon, S. W.*; Suttrop, W.*; Wolfrum, E.*; Isayama, Akihiko; Urano, Hajime; Kamada, Yutaka; JT-60 Team

In JT-60U, the ELM heatload can be reduced by together with increasing the ELM frequency by injecting electron cyclotron wave (ECW) near the top of pedestal. In order to understand the required and optimum condition for the ELM control, edge ECW injection experiments have been performed in ASDEX Upgrade and KSTAR. As a result, clear increase in the ELM frequency was observed in all devices, but the level of ELM mitigation depends on the experimental condition.