Japan Geoscience Union Meeting 2019

Presentation information

[E] Oral

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

[P-EM13] Inner magnetosphere: Recent understanding and new insights

Wed. May 29, 2019 10:45 AM - 12:15 PM A04 (TOKYO BAY MAKUHARI HALL)

convener:Yusuke Ebihara(Research Institute for Sustainable Humanosphere, Kyoto University), Danny Summers(Memorial University of Newfoundland), Yoshizumi Miyoshi(Institute for Space-Earth Environmental Research, Nagoya University), Shinji Saito(Graduate School of Science, Nagoya University), Chairperson:Yusuke Ebihara(RISH, Kyoto University), Shinji Saito(ISEE, Nagoya University)

11:25 AM - 11:40 AM

[PEM13-19] Substorm-associated particle injection near/at geosynchronous orbit: Observations from ERG and GOES

*Tzu-Fang Chang1,2, Chio-Zong Cheng2, Sunny Wing-Yee Tam2, Chih-Yu Chiang2, Yoshizumi Miyoshi1, Tomoaki Hori1, Takefumi Mitani3, Takeshi Takashima3, Ayako Matsuoka3, Mariko Teramoto1, Iku Shinohara3 (1.Institute for Space-Earth Environmental Research, Nagoya University, Japan, 2.Institute of Space and Plasma Sciences, National Cheng Kung University, Tainan, Taiwan, 3.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Japan)

Keywords:ERG, Arase, substorm injection, drift echoes, relativistic effects

The injection of electrons during the substorm event, occurring on Apr. 5, 2017, was observed by the ERG (Arase), GOES-15 and GOES-13 spacecraft near/at geosynchronous orbit. The ERG satellite observed the nearly-dispersionless injection and the subsequent drift echoes while the GOES-15 and GOES-13 captured the drift echoes with dispersion. The multipoint observations provide constraints for us to simulate the substorm-associated injection. We improve an existing model in the literature to study the substorm injection event. Since the electron energies of interest are comparable to the rest mass energy, our work further provides the relativistic form of the previous model and employs a semi-empirical model instead of a dipole-based one in the previous study. Our simulations successfully reproduce the key features of the nearly-dispersionless injection and the drift echoes. The periods of drift echoes show a better fit to the spacecraft observations when relativistic effects are taken into account. The substorm-associated injection event can be better simulated by the further-developed model shown in this study.