1. Department of Electrical and Electronic Engineering, Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto,
Utsunomiya, Tochigi 321-8585, Japan
2. Graduate School of Science and Engineering for Research, University of Toyama, Toyama, Toyama 930-8555,
Japan
3. School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
4. School of Physics, University College Dublin, Belfield, Dublin 4, Ireland
5. Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology (QST),
Kizugawa, Kyoto 619-0215, Japan
6. National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Gofi 509-5292,
Japan
7. Department of Fusion Science, SOKENDAI (The Graduate University of Advanced Studies), Toki, Gifu 509-5292,
Japan