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

Mon. May 21, 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), Miyoshi Yoshizumi(ISEE, Nagoya University)

11:30 AM - 11:45 AM

[PEM16-04] Electron Scattering by Chorus Waves Generating Pulsating Aurora

★Invited Papers

*Satoshi Kasahara1, Yoshizumi Miyoshi2, Shoichiro Yokota3, Takefumi Mitani4, Yoshiya Kasahara5, Shoya Matsuda2, Atsushi Kumamoto6, Ayako Matsuoka4, Yoichi Kazama7, Harald U Frey8, Vassilis Angelopulos9, Satoshi Kurita2, Kunihiro Keika1, Kanako Seki1, Iku Shinohara4 (1.The University of Tokyo, 2.Nagoya University, 3.Osaka University, 4.ISAS, 5.Kanazawa University, 6.Tohoku University, 7.ASIAA, 8.UCB, 9.UCLA)

Keywords:pitch angle scattering, chorus waves, ERG (Arase)

Pulsating aurorae, which are quasiperiodic, blinking patches of light tens to hundreds of kilometres across, appear at altitudes of about 100 kilometres in the high-latitude regions of both hemispheres, and multiple patches often cover the entire sky. This auroral pulsation, with periods of several to tens of seconds, is generated by the intermittent precipitation of energetic electrons (several to tens of kiloelectronvolts) arriving from the magnetosphere and colliding with the atoms and molecules of the upper atmosphere. A possible cause of this precipitation is the interaction between magnetospheric electrons and electromagnetic waves called whistler-mode chorus waves. However, no direct observational evidence of this interaction has been obtained so far. Here we report that energetic electrons are scattered by chorus waves, resulting in their precipitation. Our observations were made in March 2017 with a magnetospheric spacecraft equipped with a high-angular-resolution electron sensor and electromagnetic field instruments. The measured quasiperiodic precipitating electron flux was sufficiently intense to generate a pulsating aurora, which was indeed simultaneously observed by a ground auroral imager.