1. Kyoto University, Department of Nuclear Engineering, Kyoto 606-8501, Japan
2. National Institute for Fusion Science, Toki, Gifu 509-5292, Japan
3. Tohoku University, Graduate School of Engineering, Sendai 980-8579, Japan
4. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8072
5. Nagoya University, Department of Energy Engineering and Science, 464-8603, Japan
6. Hokkaido University, Graduate School of Engineering, Sapporo 060-8628, Japan
7. Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-17491 Greifswald, Germany