1. Institute of Geology and Geophysics; Chinese Academy of Sciences; Beijing China
2. Space Research Institute; Austrian Academy of Sciences; Graz Austria
3. CAS Key Laboratory of Basic Plasma Physics, School of Earth and Space Sciences; University of Science and Technology of China; Hefei China
4. Institute of Geophysics and Planetary Physics; University of California; Los Angeles California USA
5. Institut für Geophysik und extraterrestrische Physik; Technische Universität Braunschweig; Brunswick Germany
6. Space Science Laboratory; University of California; Berkeley California USA