Confirmation of EMIC wave-driven relativistic electron preci

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TitleConfirmation of EMIC wave-driven relativistic electron precipitationAbstractElectromagnetic ion cyclotron (EMIC) waves are believed to be an important source of pitch angle scattering driven relativistic electron loss from the radiation belts. To date, investigations of this precipitation have been largely theoretical in nature, limited to calculations of precipitation characteristics based on wave observations and small-scale studies. Large-scale investigation of EMIC wave-driven electron precipitation has been hindered by a lack of combined wave and precipitation measurements. Analysis of electron flux data from the POES (Polar Orbiting Environmental Satellites) spacecraft has been suggested as a means of investigating EMIC wave-driven electron precipitation characteristics, using a precipitation signature particular to EMIC waves. Until now the lack of supporting wave measurements for these POES-detected precipitation events has resulted in uncertainty regarding the driver of the precipitation. In this paper we complete a statistical study comparing POES precipitation measurements with wave data from several ground-based search coil magnetometers; we further present a case study examining the global nature of this precipitation. We show that a significant proportion of the precipitation events correspond with EMIC wave detections on the ground; for precipitation events that occur directly over the magnetometers, this detection rate can be as high as 90%. Our results demonstrate that the precipitation region is often stationary in magnetic local time, narrow in L, and close to the expected plasmapause position. Predominantly, the precipitation is associated with helium band rising tone Pc1 waves on the ground. The success of this study proves the viability of POES precipitation data for investigating EMIC wave-driven electron precipitation. ©2016. American Geophysical Union. All Rights Reserved.AcknowledgementsThe research leading to these results has received funding from the European Communityâ€™s Seventh Framework Programme (FP7/2007â€"2013) under grant agreement 263218. The authors wish to thank the personnel who developed, maintain, and operate the NOAA/POES spacecraft; the Halley search coil magnetometer, AARDDVARK, and riometer instruments; the CARISMA search coil magnetometer chain; the SodankylÃ¤ Geophysical Observatory (SGO) search coil magnetometer and riometer chains; and the Athabasca magnetometer. Support for the Halley search coil magnetometer was provided by U.S. National Science Foundation grants PLR-1341493 to Augsburg College and PLR-1341677 to the University of New Hampshire. CARISMA is operated by the University of Alberta, funded by the Canadian Space Agency. The Athabasca induction coil magnetometer is operated by Martin Connors of the Centre for Science, Athabasca University, Athabasca, Alberta, Canada, and Kazuo Shiokawa of the Institute for Space-Earth Environmental Research, Nagoya University, Japan. The data used in this paper are available at NOAAâ€™s National Geophysical Data Center (NGDCâ€"POES MEPED data), the British Antarctic Surveyâ€™s Physical Sciences Division Data Access Framework (SCM, riometer, and AARDDVARK data), the University of Alberta CARISMA data repository (SCM data), the SGO (SCM and riometer dataâ€"available on request), and the ISEE magnetometer data site (http://stdb2.stelab.nagoya-u.ac.jp/ magne/index.html) for all years of operation.Funding DetailsAU, Athabasca University; 263218; UNH, University of New Hampshire; Nagoya University; http://stdb2.stelab.nagoya-u.ac.jp/magne/index.html; University of Alberta; FP7, Seventh Framework Programme; PLR-1341677; PLR-1341493; CSA, Canadian Space Agency

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1st AuthorHendry, A. AuthorHendry, A.Rodger, C.Clilverd, M.Engebretson, M.Mann, I.Lessard, M.Raita, T.Milling, D.Year2016JournalJournal of Geophysical Research: Space PhysicsVolume121Number6Pages5366-5383DOI10.1002/2015JA022224URLhttps://www.scopus.com/inward/recor.....508a7760bc3ef7c17df03a8edPublisherBlackwell Publishing LtdAuthor Keywordselectromagnetic ion cyclotronEMIC wavesenergetic electron precipitationmagnetometerPOES

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CitationHendry, A., Rodger, C., Clilverd, M., Engebretson, M., Mann, I., Lessard, M., Raita, T. and Milling, D. (2016). Confirmation of EMIC wave-driven relativistic electron precipitation. Journal of Geophysical Research: Space Physics, 121(6): 5366-5383