1. Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
2. Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, South Korea
3. National Fusion Research Institute, Daejeon 34133, South Korea
4. Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
5. Columbia University, New York, New York 10027, USA
6. University of California at Davis, Davis, California 95616, USA
7. Kyungpook National University, Daegu 41566, South Korea