Characteristics and Generation of Low‐Frequency Magnetosonic Waves Below the Proton Gyrofrequency

TitleCharacteristics and Generation of Low‐Frequency Magnetosonic Waves Below the Proton Gyrofrequency
Publication TypeJournal Article
Year of Publication2019
AuthorsTeng, S, Li, W, Tao, X, Ma, Q, Shen, X
JournalGeophysical Research Letters
Volume46
Issue21
Pagination11652 - 11660
Date Published10/2019
ISSN0094-8276
KeywordsBelow the proton gyrofrequency; Low frequency magnetosonic wave; Van Allen Probes; wave generation; Wave propagation characteristics
AbstractWe report a Van Allen Probes observation of large‐amplitude magnetosonic waves with the peak intensity below the proton gyrofrequency (fcp), which may potentially be misinterpreted as electromagnetic ion cyclotron waves. The frequency spacing of the wave harmonic structure suggests that these magnetosonic waves are excited at a distant source region and propagate radially inward. We also conduct a statistical analysis of low‐frequency magnetosonic waves below fcp based on the Van Allen Probes data from October 2012 to December 2018. The spatial distribution shows that these low‐frequency magnetosonic emissions are dominantly observed inside the plasmasphere from the prenoon to the midnight sector within 5° of the geomagnetic equator and typically have modest‐to‐strong wave amplitudes ranging from tens of pT to hundreds of pT. Our study provides insight into understanding the generation and propagation of these low‐frequency magnetosonic waves in the Earth's inner magnetosphere.
URLhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL085372
DOI10.1029/2019GL085372
Short TitleGeophys. Res. Lett.


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