JpGU-AGU Joint Meeting 2017

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[EE] Oral

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

[P-EM14] [EE] Dynamics in magnetosphere and ionosphere

Sun. May 21, 2017 1:45 PM - 3:15 PM 105 (International Conference Hall 1F)

convener:Tomoaki Hori(Graduate school of Science, University of Tokyo), Yoshimasa Tanaka(National Institute of Polar Research), 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), Chairperson:Atsuki Shinbori(ISEE, Nagoya Univ.), Chairperson:Shin'ya Nakano(The Institute of Statistical Mathematics), Chairperson:Shin-ichiro Oyama(ISEE, Nagoya Univ.)

2:50 PM - 3:05 PM

[PEM14-28] Energetic electron precipitation and auroral morphology at the substorm recovery phase

*Shin-ichiro Oyama1, Antti Kero2, Craig J Rodger3, Mark A Clilverd4, Yoshizumi Miyoshi1, Noora Partamies5,6, Esa Turunen2, Tero Raita2, Pekka T Verronen7, Shinji Saito1 (1.Institute for Space-Earth Environmental Research, Nagoya University, 2.University of Oulu, 3.University of Otago, 4.British Antarctic Survey, 5.The University Centre in Svalbard, 6.Birkeland Centre for Space Science, 7.Finnish Meteorological Institute)

Keywords:aurora, ionosphere, EISCAT, KAIRA, energetic electron precipitation

It is well known that auroral patterns at the substorm recovery phase are characterized by diffuse or patch structures with intensity pulsation. According to satellite measurements and simulation studies, the precipitating electrons associated with these aurorae can reach or exceed energies of a few hundred keV through resonant wave-particle interactions in the magnetosphere. However, because of difficulty of simultaneous measurements, the dependency of energetic electron precipitation (EEP) on auroral morphological changes in the mesoscale has not been investigated to date. In order to study this dependency, we have analyzed data from the European Incoherent Scatter (EISCAT) radar, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) riometer, collocated cameras, ground-based magnetometers, the Van Allen Probe satellites, Polar Operational Environmental Satellites (POES), and the Antarctic-Arctic Radiation-belt (Dynamic) Deposition-VLF Atmospheric Research Konsortium (AARDDVARK). Here we undertake a detailed examination of two case studies. The selected two events suggest that the highest energy of EEP on those days occurred with auroral patch formation from post-midnight to dawn, coinciding with the substorm onset at local midnight. Measurements of the EISCAT radar showed ionization as low as 65 km altitude, corresponding to EEP with energies of about 500 keV.