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In Situ Observations of Whistler‐Mode Chorus Waves Guided by Density Ducts
Author(s) -
Chen Rui,
Gao Xinliang,
Lu Quanming,
Chen Lunjin,
Tsurutani Bruce T.,
Li Wen,
Ni Binbin,
Wang Shui
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028814
Subject(s) - chorus , van allen radiation belt , physics , magnetosphere , geophysics , geology , electron density , van allen probes , computational physics , electron , magnetic field , art , literature , quantum mechanics
In this paper, we report the proof of the existence of density ducts in the Earth's magnetosphere by studying in situ observations of whistler‐mode chorus waves using NASA's Van Allen Probe‐A data. Chorus waves, originally excited inside the density ducts with wave normal angles (WNAs) smaller than the Gendrin angle at the near‐equatorial region, are efficiently confined to a limited area inside density ducts (i.e., ducted regions), and remain with small WNAs as they propagate toward higher latitudes. The ducted region becomes narrower for the higher‐frequency waves. Chorus waves with WNAs larger than the Gendrin angle are not guided by density ducts. Our study reveals that density ducts can effectively control the property and distribution of chorus waves, and may ultimately regulate electron dynamics in the Earth's or other planetary radiation belts.