1. Japan Atomic Energy Research Institute Naka Fusion Research Establishment, Department of Fusion Plasma Research Naka-machi, Naka-gun, Ibaraki-ken, Japan
2. Japan Atomic Energy Research Institute Advanced Science Research Center, Naka-machi, Naka-gun, Ibaraki-ken, Japan
3. University of Electro-Communications Department of Computer Science and Information Mathematics Faculty of Electro-Communications 1-5-1 Chofugaoka, Chofu 182, Japan