[P-EM11] Dynamics of the Inner Magnetospheric System

[PEM11-09] Multipoint Measurement of Fine-Structured EMIC Waves by Arase, Van Allen Probe A, and Ground Stations

*松田 昇也¹、三好 由純²、笠原 禎也¹、Lauren Blum³、Chris Colpitts⁴、浅村 和史⁵、笠羽 康正⁶、松岡 彩子⁷、土屋 史紀⁶、熊本 篤志⁶、寺本 万里子⁸、中村 紗都子²、北原 理弘²、篠原 育⁵、Geoffrey Reeves⁹、Harlan Spence¹⁰、塩川 和夫²、長妻 努¹¹、大山 伸一郎^2,12、Ian Mann¹³ (1.金沢大学、2.名古屋大学 宇宙地球環境研究所、3.コロラド大学、4.ミネソタ大学、5.宇宙航空研究開発機構 宇宙科学研究所、6.東北大学、7.京都大学、8.九州工業大学、9.ロスアラモス国立研究所、10.ニューハンプシャー大学、11.情報通信研究機構、12.国立極地研究所、13.アルバータ大学)

キーワード：あらせ衛星、Van Allen Probes、PWING、CARISMA、電磁イオンサイクロトロン波

Electromagnetic ion cyclotron (EMIC) waves are an important plasma waves that control energetic ion and relativistic electron precipitations in the terrestrial inner magnetosphere. We successfully measured latitudinally propagating EMIC waves using multipoint measurement data observed by Japanese Arase, U.S. Van Allen Probes, the PWING ground based magnetometer, and the CARISMA magnetometer array during a field-line conjunction event on 18 April 2019. By comparing the footprints and wave spectra obtained by the aforementioned spacecraft and ground stations, we concluded that the observed EMIC wave activity was spatially localized (185 km latitudinal width at an auroral altitude of 100 km) and the spatial scale of the wave propagation duct was smaller (<80 km) than the EMIC wave activity region. The estimated latitudinal width of the propagation duct is consistent with a comprehensive study of the isolated proton auroras (IPAs) by Sakaguchi et al. (2015), suggesting that IPAs are a visual manifest of wave-particle interaction regions. We also found that the clear heating of protons with local pitch-angles of approximately 30 and 150 degrees was detected by Arase concurrently with the appearance of fine-structured EMIC waves. This thermal ion distribution was also observed in the equatorial region by ECT/HOPE aboard Van Allen Probe A. Additionally, the thermal He⁺ heating was observed coincident with fine-structured EMIC waves.