1. Osaka University, Institute of Laser Engineering 2-6, Yamadaoka, Suita 565, Japan
2. Kyoto University Institute of Atomic Energy, Uji, Kyoto 611, Japan
3. Toshiba Corporation Research and Development Center, 4-1, Ukishima, Kawasaki 210, Japan
4. University of Texas-Austin Institute for Fusion Study, Austin, Texas 78712
5. Institute for Future Technology 2-1, Kitanomaru-Koen, Chiyoda-kuf Tokyo 102, Japan