Japan Geoscience Union Meeting 2015

Presentation information

International Session (Oral)

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

[P-EM10] Study of coupling processes in solar-terrestrial system

Thu. May 28, 2015 4:15 PM - 6:00 PM A01 (APA HOTEL&RESORT TOKYO BAY MAKUHARI)

Convener:*Mamoru Yamamoto(Research Institute for Sustainable Humanosphere, Kyoto University), Satonori Nozawa(Solar-Terrestrial Environment Laboratory), Yasunobu Ogawa(National Institute of Polar Research), Hiroyuki Hashiguchi(Research Institute for Sustainable Humanosphere, Kyoto University), Akimasa Yoshikawa(Department of Earth and Planetary Sciences, Kyushu University), Chair:Satonori Nozawa(Solar-Terrestrial Environment Laboratory)

5:15 PM - 5:30 PM

[PEM10-27] Comprehensive observations on the pulsating aurora from satellite and ground-observations

*Yoshizumi MIYOSHI1, Shin-ichiro OYAMA1, Shinji SAITO1, Satoshi KURITA1, Hitoshi FUJIWARA2, Ryuho KATAOKA3, Yusuke EBIHARA4, Craig Kletzing5, Geoff Reeves6, Ondrej Santolik7, Mark Clilverd8, Craig Rodger9, Esa Turunen10, Fuminori TSUCHIYA11 (1.Solar-Terrestrial Environment Laboratory, Nagoya University, 2.Seikei University, 3.National Institute of Polar Research, 4.RISH, Kyoto University, 5.University of Iowa, USA, 6.Los Alamos National Laboratory, USA, 7.Charles University in Prague, Czech Rep., 8.British Antarctic Survey, UK, 9.University of Otago, NZ, 10.Sodankyla Geophysical Observatory, University of Oulu, Finland, 11.PPARC, Tohoku University)

Keywords:pulsating aurora, EISCAT, high energy electron precipiation

The pulsating aurora are caused by intermittent precipitations of tens keV electrons. The modulation for the pitch angle scattering take place at the magnetosphere via whistler mode wave-particle interactions. Usually, it is not possible to detect the electron flux modulation at the magnetosphere because of the small loss cone angle. On the other hand, an integration of several ground instruments provides the data for precipitating electrons. Here, we report an ideal observation for the pulsating aurora in November 2012. During the period,the pulsating aurora are observed at Tromso, Norway. The VHF radar obtained the height-resolved electron density profile during the period, which can be used to estimate the electron energy spectrum. As a result of the EISCAT observations, we identify at least 200 keV electrons precipitate simultaneously associated with the pulsating aurora. The riometer and subionospheric radio wave networks support this observation, and the radio wave network identified that the energetic electron precipitation occurred from 01 MLT to 07 MLT. During this period, the footprint of the Van Allen Probe-A satellite was very close to Tromso and the satellite observed rising tone emissions of the lower-band chorus (LBC) waves near the equatorial plane. Using the satellite observed LBC and trapped electrons as an initial condition, we conducted a computer simulation of the wave-particle interactions. The simulation showed simultaneous precipitation of electrons at both tens of keV and a few hundred keV. And the simulated energy spectrum is consistent with that derived from the EISCAT observation. From a comparison between the simulation and the observations, we specified the strong diffusion at ~100 keV, and the propagating whistler mode waves cause further precipitation at ~200 keV. This result revealed that electrons with a wide energy range simultaneously precipitate into the ionosphere in association with the pulsating aurora.