Response of ionosphere/thermosphere over European sector during the First G3 extreme geomagnetic storm in 25 solar cycle

Jeong-Heon Kim1, Young-Sil Kwak1, Changsup Lee2, Jaewook Lee3, Hosik Kam1, Yang Tae-yong1, Geonhwa Jee2 and Yongha Kim3, (1)KASI Korea Astronomy and Space Science Institute, Daejeon, South Korea, (2)Korea Polar Research Institute, Division of Atmospheric Sciences, Incheon, South Korea, (3)Chungnam National University, Daejeon, South Korea