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Multipoint Observations of Quasiperiodic Emission Intensification and Effects on Energetic Electron Precipitation
Author(s) -
Li Jinxing,
Bortnik Jacob,
Ma Qianli,
Li Wen,
Shen Xiaochen,
Nishimura Yukitoshi,
An Xin,
Thaller Scott,
Breneman Aaron,
Wygant John,
Kurth William S.,
Hospodarsky George B.,
Hartley David P.,
Reeves Geoffrey D.,
Funsten Herbert O.,
Blake J. Bernard,
Spence Harlan,
Baker Daniel N.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028484
Subject(s) - physics , quasiperiodic function , chorus , magnetosphere , electron , atmospheric sciences , electron precipitation , atmosphere (unit) , amplitude , plasma , computational physics , electron density , environmental science , meteorology , nuclear physics , optics , art , literature , condensed matter physics
The two Van Allen Probes simultaneously recorded a coherently modulated quasiperiodic (QP) emission that persisted for 3 h. The magnetic field pulsation at the locations of the two satellites showed a substantial difference, and their frequencies were close to but did not exactly match the repetition frequency of QP emissions for most of the time, suggesting that those coherent QP emissions probably originated from a common source, which then propagated over a broad area in the magnetosphere. The QP emissions were amplified by local anisotropic electron distributions, and their large‐scale amplitudes were modulated by the plasma density. A novel observation of this event is that chorus waves at frequencies above QP emissions exhibit a strong correlation with QP emissions. Those chorus waves intensified when the QP emissions reach their peak frequency. This indicates that embryonic QP emissions may be critical for its own intensification as well as chorus waves under certain circumstances. A Low‐Earth‐Orbit POES satellite observed enhanced energetic electron precipitation in conjunction with the Van Allen Probes, providing direct evidence that QP emissions precipitate energetic electrons into the atmosphere. This scenario is quantitatively confirmed by our quasilinear diffusion simulation results.