Electron precipitation from EMIC waves: a case study from 31 May 2013

On 31 May 2013 several rising-tone electromagnetic ion-cyclotron (EMIC) waves with intervals of pulsations of diminishing periods (IPDP) were observed in the magnetic local time afternoon and evening sectors during the onset of a moderate/large geomagnetic storm. The waves were sequentially observed in Finland, Antarctica, and western Canada. Co-incident electron precipitation by a network of ground-based Antarctic Arctic Radiation-belt Dynamic Deposition VLF Atmospheric Research Konsortia (AARDDVARK) and riometer instruments, as well as the Polar-orbiting Operational Environmental Satellite (POES) electron telescopes, was also observed. At the same time POES detected 30-80 keV proton precipitation drifting westwards at locations that were consistent with the ground-based observations, indicating substorm injection. Through detailed modelling of the combination of ground and satellite observations the characteristics of the EMIC-induced electron precipitation were identified as: latitudinal width of 2-3° or ΔL=1 Re, longitudinal width ~50° or 3 hours MLT, lower cut off energy 280 keV, typical flux 1×104 el. cm-2 sr-1 s-1 >300 keV. The lower cutoff energy of the most clearly defined EMIC rising tone in this study confirms the identification of a class of EMIC-induced precipitation events with unexpectedly low energy cutoffs of <400 keV.


Publication status:
Authors: Clilverd, Mark A. ORCIDORCID record for Mark A. Clilverd, Duthie, Roger ORCIDORCID record for Roger Duthie, Hardman, Rachael, Hendry, Aaron T., Rodger, Craig J., Raita, Tero, Engebretson, Mark, Lessard, Marc R., Danskin, Donald, Milling, David K.

On this site: Mark Clilverd, Roger Duthie, Roger Duthie
1 May, 2015
Journal of Geophysical Research: Space Physics / 120
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