1. Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China
2. College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing China
3. Swedish Institute of Space Physics Kiruna Sweden
4. Mohe Observatory of Geophysics Beijing National Observatory of Space Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China
5. Beijing International Center for Mathematical Research Peking University Beijing China
6. Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA