1. Data Analysis Center for Geomagnetism and Space Magnetism, Graduate School of Science Kyoto University Kyoto Japan
2. Department of Earth and Planetary Science Kyushu University Fukuoka Japan
3. International Center for Space Weather Science and Education Kyushu University Fukuoka Japan
4. The Johns Hopkins University Applied Physics Laboratory Laurel Maryland USA
5. Applied Electromagnetic Research Institute National Institute of Information and Communications Technology Tokyo Japan
6. Institute of Geophysics and Planetary Physics University of California Los Angeles California USA