Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

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

[P-EM16] Dynamics of Earth's Inner Magnetosphere and Initial Results from Arase

Tue. May 22, 2018 10:45 AM - 12:15 PM 303 (3F International Conference Hall, Makuhari Messe)

convener:Danny Summers(Memorial University of Newfoundland), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Keisuke Hosokawa(電気通信大学大学院情報理工学研究科, 共同), Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Chairperson:Hosokawa Keisuke(The University of Electro-Communications)

10:45 AM - 11:00 AM

[PEM16-25] On the field line length dependence of variations in anisotropies for pitch angle distributions of keV electrons at dipolarization sites in the tailside

★Invited Papers

*Kaiti Wang1, Zhuo-Ren Lang2, Ching-Huei Lin3, Tohru Hada4, Alfred B. C. Chen2, Toshi Nishimura5 (1.Tamkang Univ., 2.NCKU, 3.Chien-Hsin Univ., 4.Kyushu Univ., 5.Boston Univ.)

Keywords:pitch angle distributions, dipolarization, THEMIS mission

Previous studies had reported observations from various satellite missions on changes in pitch angle distributions of electrons during dipolarization periods at Earth’s tailside associated with geomagnetic activities. In this study, we quantitatively analyzed the variations in anisotropies for pitch angle distributions of electrons based on observations from 2008 to 2011, by particle instruments ESA and SST onboard the probes of THEMIS mission, at dipolarization sites in the inner plasma sheet. The ratio of this anisotropy during dipolarization to that before dipolarization is found to overall exhibit an increasing trend on its upper limit as the length of field line the probe located increases, specifically for electrons with energies on the order of keV. The effectiveness of Fermi acceleration at different field line length may account for this feature. We will present these results on the aspects of observations as well as theories.