Van Allen Probes observations of chorus wave vector orientations: Implications for the chorus-to-hiss mechanism

TitleVan Allen Probes observations of chorus wave vector orientations: Implications for the chorus-to-hiss mechanism
Publication TypeJournal Article
Year of Publication2019
AuthorsHartley, DP, Kletzing, CA, Chen, L, Horne, RB, ík, O
JournalGeophysical Research Letters
Date Published02/2019
Keywordschorus waves; EMFISIS; Plasmaspheric Hiss; plasmaspheric plumes; Van Allen Probes; wave normal angle
AbstractUsing observations from the Van Allen Probes EMFISIS instrument, coupled with ray tracing simulations, we determine the fraction of chorus wave power with the conditions required to access the plasmasphere and evolve into plasmaspheric hiss. It is found that only an extremely small fraction of chorus occurs with the required wave vector orientation, carrying only a small fraction of the total chorus wave power. The exception is on the edge of plasmaspheric plumes, where strong azimuthal density gradients are present. In these cases, up to 94% of chorus wave power exists with the conditions required to access the plasmasphere. As such, we conclude that strong azimuthal density gradients are actually a requirement if a significant fraction of chorus wave power is to enter the plasmasphere and be a source of plasmaspheric hiss. This result suggests it is unlikely that chorus directly contributes a significant fraction of plasmaspheric hiss wave power.
URLhttps://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL082111
DOI10.1029/2019GL082111
Short TitleGeophys. Res. Lett.


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