Journal article
Low-harmonic magnetosonic waves observed by the Van Allen Probes
Journal of geophysical research. Space physics, Vol.120(8), pp.6230-6257
08/2015
DOI: 10.1002/2015JA021179
Abstract
Purely compressional electromagnetic waves (fast magnetosonic waves), generated at multiple harmonics of the local proton gyrofrequency, have been observed by various types of satellite instruments (fluxgate and search coil magnetometers and electric field sensors), but most recent studies have used data from search coil sensors, and many have been restricted to high harmonics. We report here on a survey of low-harmonic waves, based on electric and magnetic field data from the Electric Fields and Waves double probe and Electric and Magnetic Field Instrument Suite and Integrated Science fluxgate magnetometer instruments, respectively, on the Van Allen Probes spacecraft during its first full precession through all local times, from 1 October 2012 to 13 July 2014. These waves were observed both inside and outside the plasmapause (PP), at L shells from 2.4 to ~6 (the spacecraft apogee), and in regions with plasma number densities ranging from 10 to >1000 cm−3. Consistent with earlier studies, wave occurrence was sharply peaked near the magnetic equator. Waves appeared at all local times but were more common from noon to dusk, and often occurred within 3 h after substorm injections. Outside the PP occurrence maximized broadly across noon, and inside the PP occurrence maximized in the dusk sector, in an extended plasmasphere. We confirm recent ray-tracing studies showing wave refraction and/or reflection at PP-like boundaries. Comparison with waveform receiver data indicates that in some cases these low-harmonic magnetosonic wave events occurred independently of higher-harmonic waves; this indicates the importance of including this population in future studies of radiation belt dynamics.
Details
- Title: Subtitle
- Low-harmonic magnetosonic waves observed by the Van Allen Probes
- Creators
- J. L Posch - Augsburg UniversityM. J Engebretson - Augsburg UniversityC. N Olson - Augsburg UniversityS. A Thaller - University of MinnesotaA. W Breneman - University of MinnesotaJ. R Wygant - University of MinnesotaS. A Boardsen - University of Maryland, BaltimoreC. A Kletzing - University of IowaC. W Smith - University of New HampshireG. D Reeves - Los Alamos National Laboratory
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.120(8), pp.6230-6257
- Publisher
- Blackwell Publishing Ltd
- DOI
- 10.1002/2015JA021179
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 28
- Grant note
- DOI: 10.13039/100000001, name: National Science Foundation, award: AGS‐1202267, PLR‐1341493; DOI: 10.13039/100000104, name: National Aeronautics and Space Administration, award: NAS5‐01072
- Language
- English
- Date published
- 08/2015
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984199779702771
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