College of Science, Donghua University, Shanghai 201620;
School of Physics and Electronic Engineering, Anqing Normal University, Anqing 246133;
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031;
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031;
College of Science, Donghua University, Shanghai 201620;
Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031;