Journal article
Van Allen probes, NOAA, GOES, and ground observations of an intense EMIC wave event extending over 12 h in magnetic local time
Journal of geophysical research. Space physics, Vol.120(7), pp.5465-5488
07/2015
DOI: 10.1002/2015JA021227
Abstract
Although most studies of the effects of electromagnetic ion cyclotron (EMIC) waves on Earth's outer radiation belt have focused on events in the afternoon sector in the outer plasmasphere or plume region, strong magnetospheric compressions provide an additional stimulus for EMIC wave generation across a large range of local times and L shells. We present here observations of the effects of a wave event on 23 February 2014 that extended over 8 h in UT and over 12 h in local time, stimulated by a gradual 4 h rise and subsequent sharp increases in solar wind pressure. Large‐amplitude linearly polarized hydrogen band EMIC waves (up to 25 nT p‐p) appeared for over 4 h at both Van Allen Probes, from late morning through local noon, when these spacecraft were outside the plasmapause, with densities ~5–20 cm−3. Waves were also observed by ground‐based induction magnetometers in Antarctica (near dawn), Finland (near local noon), Russia (in the afternoon), and in Canada (from dusk to midnight). Ten passes of NOAA‐POES and METOP satellites near the northern foot point of the Van Allen Probes observed 30–80 keV subauroral proton precipitation, often over extended L shell ranges; other passes identified a narrow L shell region of precipitation over Canada. Observations of relativistic electrons by the Van Allen Probes showed that the fluxes of more field‐aligned and more energetic radiation belt electrons were reduced in response to both the emission over Canada and the more spatially extended emission associated with the compression, confirming the effectiveness of EMIC‐induced loss processes for this event.
Key Points
Compression‐induced EMIC waves were observed across 12 h of local time
EMIC‐triggered emissions appeared during the strongest compression
Intense EMIC waves outside the plasmasphere depleted the radiation belts
Details
- Title: Subtitle
- Van Allen probes, NOAA, GOES, and ground observations of an intense EMIC wave event extending over 12 h in magnetic local time
- Creators
- M. J Engebretson - Augsburg UniversityC. A Kletzing - University of IowaD. N Baker - University of Colorado BoulderJ. L Posch - Augsburg UniversityJ. R Wygant - University of MinnesotaM. R Lessard - University of New HampshireC.‐L Huang - University of New HampshireH. E Spence - University of New HampshireC. W Smith - University of New HampshireH. J Singer - National Oceanic and Atmospheric AdministrationY Omura - Kyoto UniversityR. B Horne - British Antarctic SurveyG. D Reeves - Los Alamos National LaboratoryM Gkioulidou - Johns Hopkins University Applied Physics LaboratoryK Oksavik - University of BergenI. R Mann - University of AlbertaT Raita - University of OuluK Shiokawa - Nagoya University
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.120(7), pp.5465-5488
- DOI
- 10.1002/2015JA021227
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 24
- Grant note
- NSF (ANT‐1142045; PLR‐1341493) NASA (NAS5‐01072) Augsburg College and NSF (ANT‐1141987; PLR‐1341677) Research Council of Norway (223252; 212014)
- Language
- English
- Date published
- 07/2015
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199749802771
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