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Multipoint Observations of Quasiperiodic Emission Intensification and Effects on Energetic Electron Precipitation
Journal article   Open access   Peer reviewed

Multipoint Observations of Quasiperiodic Emission Intensification and Effects on Energetic Electron Precipitation

Jinxing Li, Jacob Bortnik, Qianli Ma, Wen Li, Xiaochen Shen, Yukitoshi Nishimura, Xin An, Scott Thaller, Aaron Breneman, John Wygant, …
Journal of geophysical research. Space physics, Vol.126(2), e2020JA028484
02/2021
DOI: 10.1029/2020JA028484
url
https://www.osti.gov/biblio/1780105View
Open Access

Abstract

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.
Physical Sciences Astronomy & Astrophysics Science & Technology

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