Journal article
Statistical distribution of EMIC wave spectra: Observations from Van Allen Probes
Geophysical research letters, Vol.43(24), pp.12,348-12,355
12/28/2016
DOI: 10.1002/2016GL071158
Abstract
It has been known that electromagnetic ion cyclotron (EMIC) waves can precipitate ultrarelativistic electrons through cyclotron resonant scattering. However, the overall effectiveness of this mechanism has yet to be quantified, because it is difficult to obtain the global distribution of EMIC waves that usually exhibit limited spatial presence. We construct a statistical distribution of EMIC wave frequency spectra and their intensities based on Van Allen Probes measurements from September 2012 to December 2015. Our results show that as the ratio of plasma frequency over electron gyrofrequency increases, EMIC wave power becomes progressively dominated by the helium band. There is a pronounced dawn‐dusk asymmetry in the wave amplitude and the frequency spectrum. The frequency spectrum does not follow the commonly used single‐peak Gaussian function. Incorporating these realistic EMIC wave frequency spectra into radiation belt models is expected to improve the quantification of EMIC wave scattering effects in ultrarelativistic electron dynamics.
Key Points
Statistical distribution of the EMIC wave frequency spectrum is collected by using Van Allen Probes measurements
The RMS EMIC wave amplitude becomes stronger with increasing levels of geomagnetic activity
EMIC wave power is dominated by He‐band (H‐band) in high (low) fpe/fce regions
Details
- Title: Subtitle
- Statistical distribution of EMIC wave spectra: Observations from Van Allen Probes
- Creators
- X.‐J. Zhang - UCLAW. Li - NOAA Oceanic and Atmospheric ResearchR. M. Thorne - NOAA Oceanic and Atmospheric ResearchV. Angelopoulos - Planetary Science InstituteJ. Bortnik - NOAA Oceanic and Atmospheric ResearchC. A. Kletzing - University of IowaW. S. Kurth - University of IowaG. B. Hospodarsky - University of Iowa
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.43(24), pp.12,348-12,355
- DOI
- 10.1002/2016GL071158
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 8
- Grant note
- AFOSR (FA9550‐15‐1‐0158) NASA's prime (NNN06AA01C) JHU/APL (131802) NASA (NAS5‐02099; NNX14AI18G; NNX13AI61G; NNX14AN85G) NSF (AGS 1564510)
- Language
- English
- Date published
- 12/28/2016
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984429039002771
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