1. Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
2. Anhui University of Science and Technology, School of Mechanical Engineering, Huainan 232001, China
3. ITER Organization, Route de Vinon-sur-Verdon, CS 90046, 1306 St. Paul Lez Durance Cedex, France