日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM11] Dynamics of Magnetosphere and Ionosphere

2019年5月29日(水) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:中溝 葵(情報通信研究機構 電磁波研究所)、尾崎 光紀(金沢大学理工研究域電子情報学系)、藤本 晶子(九州工業大学)、堀 智昭(名古屋大学宇宙地球環境研究所)

[PEM11-P09] A statistical study of Pi2 pulsations observed in the upper ionosphere using Swarm magnetic field data

*Park Jaehee1Khan-Hyuk Kim1Junga Hwang2 (1.School of Space Research, Kyung Hee University, Gyeonggi, South Korea、2.Korea Astronomy and Space Science Institute, Daejeon,South Korea)

キーワード:Pi2 pulsations

The properties of Pi2 pulsations observed in the upper ionosphere are studied using magnetic field data acquired by the Swarm-A spacecraft in low Earth orbit (LEO) and at the low-latitude Bohyun ground station (BOH, L = 1,3) for January 2014-Jun 2015. From time intervals when Swarm-A was on the nightside (magnetic local time (MLT) = 1800-0600 hrs) and the BOH station was near midnight (MLT = 2100-0300 hrs), we identified 623 Pi2 events in the horizontal H component of the BOH data. For each event we examine the coherence between the horizontal H component on the ground and the Bx (radial) azimuthal By (azimuthal), or Bz (compressional) components at Swarm-A. Out of 623 events, the Bx-H high coherence (> 0.7) events are ~6%, the By-H high coherence events are ~4%, and the Bz-H high coherence events are ~25%. The ground-satellite high coherence events occurred when the spacecraft was located within a magnetic latitude range of ±50°. Using the ground-satellite high coherence events, we examined the latitudinal structure of the relative amplitude and phase of the ionospheric Pi2 pulsations detected at Swarm-A. Confirming previous observations at LEO, we found that the ionospheric Pi2 pulsations are characterized by symmetric odd mode standing oscillations in the north-south direction, having a node for Bx oscillation and an antinode for Bz oscillation, respectively, at the equator. This indicates that the source of ionospheric Pi2 pulsations is the plasmaspheric resonance.