[P-EM12] Dynamics of the Inner Magnetospheric System

[PEM12-16] Mode-coupling Pi2 pulsations on the off-equatorial plasmapause inferred from the Arase satellite observation

*寺本 万里子¹、松岡 彩子²、笠原 禎也³、笠羽 康正⁴、熊本 篤志⁴、土屋 史紀⁴、松田 昇也⁶、三好 由純⁵、能勢 正仁⁵、中川 朋子⁷、今城 峻⁵、小路 真史⁵、中村 紗都子⁵、篠原 育⁶ (1.九州工業大学、2.京都大学、3.金沢大学、4.東北大学、5.名古屋大学、6.宇宙航空研究開発機構 宇宙科学研究所、7.東北工業大学)

We investigated Pi2 pulsations in the electric and magnetic field and their relation to the ambient plasma density observed from the Arase satellite to explore the generation mechanism of low-latitude Pi2. At a geomagnetically quiet time, Pi2 pulsations were observed in all three components of the magnetic field and in the radial and azimuthal components of the electric field when the Arase satellite was located on the plasmapause off the equatorial plane (about 25 degrees Mlat) at midnight. The coherence and cross phase between the orthogonal electric and magnetic field components are high and approximately 90 degrees. The compressional component of the magnetic field has high coherence with the azimuthal component of the electric field. The cross phase properties indicate that the radial and field-aligned standing waves are excited on the plasmapause. These results confirm the mode coupling between the fast mode wave and Alfven waves in the plasmasphere, which was proposed by Takahashi et al. [2018].

We compared these Pi2 pulsations with those on the ground over a wide latitudinal and longitudinal range. Additionally, we discussed the generation mechanism of this event.