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An Event on Simultaneous Amplification of Exohiss and Chorus Waves Associated With Electron Density Enhancements
Author(s) -
Zhu Hui,
Shprits Yuri Y.,
Chen Lunjin,
Liu Xu,
Kellerman Adam C.
Publication year - 2018
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2017ja025023
Subject(s) - physics , hiss , electron , chorus , plasmasphere , computational physics , whistler , electron density , poynting vector , electron precipitation , geomagnetic storm , van allen radiation belt , van allen probes , instability , atomic physics , magnetosphere , plasma , solar wind , magnetic field , nuclear physics , quantum mechanics , art , literature
Whistler mode exohiss are the structureless hiss waves observed outside the plasmapause with featured equatorward Poynting flux. An event of the amplification of exohiss as well as chorus waves was recorded by Van Allen Probes during the recovery phase of a weak geomagnetic storm. Amplitudes of both types of the waves showed a significant increase at the regions of electron density enhancements. It is found that the electrons resonant with exohiss and chorus showed moderate pitch angle anisotropies. The ratio of the number of electrons resonating with exohiss to total electron number presented in‐phase correlation with density variations, which suggests that exohiss can be amplified due to electron density enhancement in terms of cyclotron instability. The calculation of linear growth rates further supports above conclusion. We suggest that exohiss waves have potential to become more significant due to the background plasma fluctuation.