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Van Allen Probes Observations of Chorus Wave Vector Orientations: Implications for the Chorus‐to‐Hiss Mechanism
Author(s) -
Hartley D. P.,
Kletzing C. A.,
Chen L.,
Horne R. B.,
Santolík O.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl082111
Subject(s) - chorus , plasmasphere , hiss , van allen probes , physics , van allen radiation belt , wave power , ray tracing (physics) , geophysics , computational physics , azimuth , astrophysics , magnetosphere , astronomy , power (physics) , optics , plasma , nuclear physics , electron , art , literature , quantum mechanics
Using 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.