1. Department of Earth, Planetary and Space Sciences and Institute of Geophysics and Planetary PhysicsUniversity of California CA Los Angeles USA
2. Department of Atmospheric and Oceanic SciencesUniversity of California CA Los Angeles USA
3. Space Research InstituteAustrian Academy of Sciences Graz Austria
4. Department of Space Physics, School of Electronic InformationWuhan University Wuhan China
5. NASA‐Goddard Space Flight Center Greenbelt MD USA
6. Department of Physics and AstronomyDartmouth College Hanover NH USA