Journal article
Origin of two-band chorus in the radiation belt of Earth
Nature communications, Vol.10(1), 4672
10/14/2019
DOI: 10.1038/s41467-019-12561-3
PMCID: PMC6791895
PMID: 31611553
Abstract
Naturally occurring chorus emissions are a class of electromagnetic waves found in the space environments of the Earth and other magnetized planets. They play an essential role in accelerating high-energy electrons forming the hazardous radiation belt environment. Chorus typically occurs in two distinct frequency bands separated by a gap. The origin of this two-band structure remains a 50-year old question. Here we report, using NASA’s Van Allen Probe measurements, that banded chorus waves are commonly accompanied by two separate anisotropic electron components. Using numerical simulations, we show that the initially excited single-band chorus waves alter the electron distribution immediately via Landau resonance, and suppress the electron anisotropy at medium energies. This naturally divides the electron anisotropy into a low and a high energy components which excite the upper-band and lower-band chorus waves, respectively. This mechanism may also apply to the generation of chorus waves in other magnetized planetary magnetospheres.
Chorus waves are crucial on radiation belt dynamics in the space of magnetized planets. Here, the authors show that initially excited single-band chorus waves can quickly accelerate medium energy electrons, and divide the anisotropic electrons into low and high energy components, which subsequently excite two-band chorus waves.
Details
- Title: Subtitle
- Origin of two-band chorus in the radiation belt of Earth
- Creators
- Jinxing Li - University of California, Los AngelesJacob Bortnik - University of California, Los AngelesXin An - University of California, Los AngelesWen Li - Boston UniversityVassilis Angelopoulos - Planetary Science InstituteRichard M. Thorne - University of California, Los AngelesChristopher T. Russell - Planetary Science InstituteBinbin Ni - Wuhan UniversityXiaochen Shen - Boston UniversityWilliam S. Kurth - University of IowaGeorge B. Hospodarsky - University of IowaDavid P. Hartley - University of IowaHerbert O. Funsten - Los Alamos National LaboratoryHarlan E. Spence - University of New Hampshire at ManchesterDaniel N. Baker - Laboratory for Atmospheric and Space Physics
- Resource Type
- Journal article
- Publication Details
- Nature communications, Vol.10(1), 4672
- DOI
- 10.1038/s41467-019-12561-3
- PMID
- 31611553
- PMCID
- PMC6791895
- NLM abbreviation
- Nat Commun
- ISSN
- 2041-1723
- eISSN
- 2041-1723
- Publisher
- Nature Publishing Group UK
- Grant note
- NNX14AI18G / ;
- Language
- English
- Date published
- 10/14/2019
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455658002771
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