University of Oulu

Oyama, S., Kero, A., Rodger, C. J., Clilverd, M. A., Miyoshi, Y., Partamies, N., Turunen, E., Raita, T., Verronen, P. T., and Saito, S. (2017), Energetic electron precipitation and auroral morphology at the substorm recovery phase, J. Geophys. Res. Space Physics, 122, 6508– 6527, doi:10.1002/2016JA023484

Energetic electron precipitation and auroral morphology at the substorm recovery phase

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Author: Oyama, S.1; Kero, A.1,2; Rodger, C. J.3;
Organizations: 1Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
2Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
3Department of Physics, University of Otago, Dunedin, New Zealand
4British Antarctic Survey, Cambridge, UK
5Department of Arctic Geophysics, University Centre in Svalbard, Longyearbyen, Norway
6Birkeland Centre for Space Science, Bergen, Norway
7Finnish Meteorological Institute, Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.9 MB)
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Language: English
Published: American Geophysical Union, 2017
Publish Date: 2019-09-24


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 hundreds of 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 postmidnight 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.

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Series: Journal of geophysical research. Space physics
ISSN: 2169-9380
ISSN-E: 2169-9402
ISSN-L: 2169-9380
Volume: 122
Issue: 6
Pages: 6508 - 6527
DOI: 10.1002/2016JA023484
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: KAIRA was funded by the University of Oulu and the FP7 European Regional Development Fund and is operated by Sodankylä Geophysical Observatory. [...] The AARDDVARK observations were obtained through funding support from the European Union Seventh Framework Programme [FP7/2007‐2013] under Plasmon grant agreement 263218. This research has been supported by a Grant‐in‐Aid for Scientific Research (15H05747, 15H05815, 16H06286, 16 K05569, 16H02230) and Special Funds for Education and Research (Energy Transport Processes in Geospace) from MEXT, Japan. P.T.V. was funded by the Academy of Finland through the project 276926 (SECTIC: Sun‐Earth Connection Through Ion Chemistry). A.K.'s work was funded by European Regional Development Fund (Regional Council of Lapland, decision A70179). N.P was funded by the Research Council of Norway/CoE under contract 223252/F50.
EU Grant Number: (263218) PLASMON - A new, ground based data-assimilative modeling of the Earth’s plasmasphere - a critical contribution to Radiation Belt modeling for Space Weather purposes
Copyright information: © 2017. American Geophysical Union. All Rights Reserved.