1. National Institute for Fusion Science, Toki 509-5292, Gifu, Japan
2. Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu, Japan
3. Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603, Japan
4. Southwestern Institute of Physics, Chengdu 610041, China
5. Department of Engineering Physics, Kyoto University, Kyoto 606-8502, Japan
6. Institute of Plasma Physics, Chinese Academy of Science, Hefei 230031, China
7. Naka Fusion Institute, Japan Atomic Energy Agency, Naka 311-0193, Ibaraki, Japan