1. Chengdu University of Technology, Chengdu, Sichuan 610059, China
2. University of Science and Technology of China, Hefei, Anhui 230027, China
3. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu, Sichuan 610059, China
4. Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China