[P-EM15] 太陽地球系結合過程の研究基盤形成

[PEM15-08] Statistical study of high energy electron precipitation based on Arase satellite - EISCAT collaborative observation data

*小川 泰信¹、吹澤 瑞貴¹、三好 由純²、細川 敬祐³、大山 伸一郎²、塩川 和夫²、関 華奈子⁴、栗田 怜⁵、浅村 和史⁶、笠原 慧⁴、三谷 烈史⁶、松田 昇也⁷、笠原 禎也⁷、加藤 雄人⁸、篠原 育⁶ (1.国立極地研究所、2.名古屋大学宇宙地球環境研究所、3.電気通信大学、4.東京大学、5.京都大学生存圏研究所、6.宇宙科学研究所、7.金沢大学、8.東北大学)

キーワード：電離圏、EISCAT、ERG、あらせ衛星

We have conducted more than 150 collaborative observations (~600 hours in total) between the Arase (ERG) satellite and EISCAT radar since March 2017. The obtained collaborative observation data have been used to publish papers based on detailed data analysis on high-energy electron precipitation into the arctic ionosphere and molecular ion upflow from the arctic ionosphere. However, the overall characteristics of many collaborative events have not been systematically analyzed and summarized.
In this paper, we report statistical results of the relationship between wave and particle data observed by the Arase satellite and ionospheric electron density data obtained with the EISCAT Tromsø radar. Their results are summarized as follows:
(1) When the amplitude of the lower-band chorus (LBC) waves is above ~18 pT, magnetospheric electrons with energies above ~160 keV undergo pitch angle scattering, and become significantly ionized at altitudes between 65-100 km.
(2) The relationship between resonance energies of pitch angle scattering and electron density increases due to energetic electron precipitation suggests that pitch-angle scattering of energetic electrons by LBC waves propagating at higher latitudes (~20 deg) rather than in the magnetic equatorial plane occurs frequently.