1. Department of Physics; Korea Advanced Institute of Science and Technology; Daejeon; South Korea
2. Solar and Space Weather Research Group; Korea Astronomy and Space Science Institute; Daejeon; South Korea
3. British Antarctic Survey; Cambridge; UK
4. Department of Earth and Planetary Sciences; Kyushu University; Fukuoka; Japan
5. GFZ German Research Center for Geosciences; Potsdam; Germany
6. Space Weather Prediction Center, NOAA; Boulder; Colorado; USA