Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM11] Dynamics of Magnetosphere and Ionosphere

Thu. May 30, 2019 10:45 AM - 12:15 PM A04 (TOKYO BAY MAKUHARI HALL)

convener:Aoi Nakamizo(Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology), Mitsunori Ozaki(Faculty of Electrical and Computer Engineering, Institute of Science and Engineering, Kanazawa University), Akiko Fujimoto(Kyushu Institute of Technology), Tomoaki Hori(Institute for Space-Earth Environmental Research, Nagoya University), Chairperson:Kunuhiro Keika(東京大学大学院理学系研究科), Shin'ya Nakano(情報・システム研究機構 統計数理研究所), Motoharu Nowada(Shandong University)

11:00 AM - 11:15 AM

[PEM11-14] Analysis on anisotropy variations for pitch angle distributions of electrons with various parameters at dipolarization sites in the inner plasma sheet

*Kaiti Wang1, Zhuo-Ren Lang2, Ching-Huei Lin3, Tohru Hada4, Toshi Nishimura5 (1.Tamkang Univ., 2.National Cheng Kung Univ., 3.Chien-Hsin Univ. of Sci. & Tech., 4.Kyushu Univ., 5.Boston Univ.)

Keywords:dipolarization, anisotropy of pitch angle distributions of electrons , observations of THEMIS mission

During geomagnetic activities, dipolarization of geomagnetic fields can been found to occur at tailside. In this study, we investigate variations in anisotropies of pitch angle distributions for electrons at 63 observed dipolarization sites around distance of 10 RE (Earth radii) near the magnetic equator in the inner plasma sheet when auroral electrojet AL index decreases. Observational data from 2008 to 2011 for electrons below ~26 keV from the instrument ESA (ElectroStatic Analyzer) onboard of THEMIS mission are adopted. Followed from our previous presentation in which the dependence of these variations on field line lengths (FLL) was focused on [Wang et al., 2018], we present new analysis results concentrating on the dependence of the changes as well as the rates of changes in FLL, magnetic field strengths, and dipolarization angles, during a dipolarizaion period. Comparisons between the anisotropy variations in pitch angle distributions of electrons and the associated bounce time of electrons, event dipolarization time, and measured environmental electric fields will also be presented and discussed.

Wang, K., Z. R. Lang, C. H. Lin, T. Hada, A. B. C. Chen, Y. Nishimura (2018). On the field line length dependence of variations in anisotropies for pitch angle distributions of keV electrons at dipolarization sites in the tailside. PEM16-25, JpGU Meeting 2018, Chiba, Japan.