Whistler interactions with density gradients in the magnetosphere

Very‐low frequency whistler‐mode waves are frequently observed in the equatorial magnetosphere. Large amplitude whistlers, capable of rapidly accelerating electrons to large energies, are typically observed to propagate at highly oblique angles relative to the background magnetic field. In this pape...

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Bibliographic Details
Published in:Journal of geophysical research. Space physics 2013-01, Vol.118 (1), p.167-172
Main Authors: Woodroffe, J. R., Streltsov, A. V.
Format: Article
Language:English
Subjects:
Duct
Geophysics
Magnetic fields
Magnetosphere
Whistler
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Summary:Very‐low frequency whistler‐mode waves are frequently observed in the equatorial magnetosphere. Large amplitude whistlers, capable of rapidly accelerating electrons to large energies, are typically observed to propagate at highly oblique angles relative to the background magnetic field. In this paper, we discuss a potential mechanism for the conversion of moderately oblique whistlers to highly oblique whistlers on a transverse gradient of the background plasma. We offer a theoretical explanation for this process and illustrate its operation using numerical simulations. This effect has been previously observed in laboratory experiments and it also provides a straightforward explanation for observations of highly oblique whistlers in magnetospheric plasmas. Key Points Two low‐frequency whistler modes are coupled at positive density gradients Coupling moves whistler from quasi‐parallel to quasi‐perpendicular propagation Coupling mechanism can explain observations of highly oblique whistlers
ISSN:2169-9380
2169-9402
DOI:10.1029/2012JA018308