University of Iowa, Room 203 Van Allen Hall Jefferson at Dubuque St., Iowa City, IA 52240, USA
University of Iowa, Room 203 Van Allen Hall Jefferson at Dubuque St., Iowa City, IA 52240, USA; Institute of Plasma Physics, CAS, Hefei, Anhui, 230031 China
University of California, Berkeley, Space Sciences Laboratory, Berkeley, CA 94720, USA