1. Keio University, Faculty of Science and Technology, 3-14-1 Hiyoshi Kouhoku-ku, Yokohama, 223 Japan
2. Toshiba Corporation Fusion Technology Development Office, 1-1-6 Uchisaiwai-cho Chiyoda-ku, Tokyo, 100 Japan
3. Toshiba Corporation Research and Development Center, 4-1 Ukishima-cho Kawasaki-ku, Kawasaki, 210 Japan
4. Tb-s/r/ta Corporation Fusion Technology Development Office, 1-1-6 Uchisaiwai-cho Chiyoda-ku, Tokyo, 100 Japan
5. Central Research Institute of Electric Power Industry Komae Research Laboratory, 11-1 Iwatokita 2-chome, Komae, Tokyo, 201 Japan
6. Central Research Institute of Electric Power Industry Socio-Economic Research Center, 1-6-1 Ohtemachi, Chiyoda-ku, Tokyo, 100 Japan