日本地球惑星科学連合2018年大会

講演情報

[JJ] Eveningポスター発表

セッション記号 P (宇宙惑星科学) » P-CG 宇宙惑星科学複合領域・一般

[P-CG23] 惑星大気圏・電磁圏

2018年5月20日(日) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:関 華奈子(東京大学大学院理学系研究科)、今村 剛(東京大学大学院 新領域創成科学研究科)、寺田 直樹(東北大学大学院理学研究科、共同)、前澤 裕之(大阪府立大学大学院理学系研究科物理科学科)

[PCG23-P08] Enceladus衛星H2Oトーラス中の弾性衝突による電子ピッチ角散乱のエネルギー依存性

*田所 裕康1加藤 雄人2 (1.武蔵野大学、2.東北大学大学院)

キーワード:エンケラドストーラス、土星磁気圏、電子中性衝突、弾性衝突、ピッチ角散乱

Water group neutrals (H2O, OH, and O) in Saturn’s inner magnetosphere play the dominant role in loss of energetic electrons and ions because of abundance of the neutrals [e.g., Paranicas et al., 2007,2008; Sittler et al., 2008]. The previous studies suggested that the neutral cloud originated from Enceladus contributes to loss processes of plasma in the inner magnetosphere. However, little has been reported on a quantitative study of the electron loss process due to electron-neutral collisions. In this study, we focus on the elastic collisional loss process with neutrals. Conducting one dimensional test-particle simulation, Tadokoro et al. [2014] examined the time variations of equatorial pitch angle distribution and electrons within loss cone through 1 keV electron pitch angle scattering due to electron-H2O elastic collisions around Enceladus when the electron flux tube passes the region of the dense H2O molecules in the vicinity of Enceladus (~380 sec). The result showed that the electrons of 11.4 % are lost in ~380 sec. Assuming the uniform azimuth H2O density structure in the torus, they also estimated the electron loss rate of 33 % during one corotation. Next remaining issue is a calculation of energy dependent electron loss rate. We show the loss rate of electrons with 500eV-50keV and the comparison of the loss rate between the high (in the vicinity of Enceladus) and low (in the Enceladus torus) H2O density regions.