1. School of Space and Environment Beihang University Beijing China
2. Key Laboratory of Space Environment Monitoring and Information Processing of MIIT Beihang University Beijing China
3. Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA
4. Department of Electrical and Computer Engineering Democritus University of Thrace Xanthi Greece
5. Institute of Space Physics and Applied Technology Peking University Beijing China
6. School of Physics and Astronomy University of Minnesota, Twin Cities Minneapolis MN USA