1. Department of Earth and Planetary Science Graduate School of Science University of Tokyo Tokyo Japan
2. Department of Geophysics Graduate School of Science Tohoku University Sendai Japan
3. Planetary Plasma and Atmospheric Research Center Graduate School of Science Tohoku University Sendai Japan
4. National Institute of Information and Communications Technology Koganei Japan
5. Laboratory for Atmospheric and Space Physics University of Colorado Boulder Boulder CO USA
6. Space Sciences Laboratory University of California Berkeley CA USA
7. Department of Physics and Astronomy University of Iowa Iowa City IA USA
8. NASA Goddard Space Flight Center Greenbelt MD USA
9. International Center for Space Weather Science and Education Kyushu University Fukuoka Japan