DOI: 10.1002/2016GL070386
论文题名: Unraveling the excitation mechanisms of highly oblique lower band chorus waves
作者: Li W. ; Mourenas D. ; Artemyev A.V. ; Bortnik J. ; Thorne R.M. ; Kletzing C.A. ; Kurth W.S. ; Hospodarsky G.B. ; Reeves G.D. ; Funsten H.O. ; Spence H.E.
刊名: Geophysical Research Letters
ISSN: 0094-8650
EISSN: 1944-8381
出版年: 2016
卷: 43, 期: 17 起始页码: 8867
结束页码: 8875
语种: 英语
英文关键词: beam instability
; lower band chorus
; oblique chorus excitation
; temperature anisotropy
Scopus关键词: Anisotropy
; Electromagnetic waves
; Electrons
; Excited states
; Magnetosphere
; Velocity distribution
; Beam instability
; Earth's magnetosphere
; Electron distributions
; Electron velocity distributions
; Excitation mechanisms
; Linear growth rate
; Lower band chorus
; Temperature anisotropy
; Atmospherics
; anisotropy
; electron density
; growth rate
; instability
; instrumentation
; magnetosphere
; obliquity
; plasma
; probe
; resonance
; temperature
; velocity profile
; wave field
英文摘要: Excitation mechanisms of highly oblique, quasi-electrostatic lower band chorus waves are investigated using Van Allen Probes observations near the equator of the Earth's magnetosphere. Linear growth rates are evaluated based on in situ, measured electron velocity distributions and plasma conditions and compared with simultaneously observed wave frequency spectra and wave normal angles. Accordingly, two distinct excitation mechanisms of highly oblique lower band chorus have been clearly identified for the first time. The first mechanism relies on cyclotron resonance with electrons possessing both a realistic temperature anisotropy at keV energies and a plateau at 100–500 eV in the parallel velocity distribution. The second mechanism corresponds to Landau resonance with a 100–500 eV beam. In both cases, a small low-energy beam-like component is necessary for suppressing an otherwise dominating Landau damping. Our new findings suggest that small variations in the electron distribution could have important impacts on energetic electron dynamics. ©2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84984815189&doi=10.1002%2f2016GL070386&partnerID=40&md5=65923464d9295df3eedfe2a0311da0c6
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9613
Appears in Collections: 科学计划与规划 气候变化与战略
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作者单位: Center for Space Physics, Boston University, Boston, MA, United States
Recommended Citation:
Li W.,Mourenas D.,Artemyev A.V.,et al. Unraveling the excitation mechanisms of highly oblique lower band chorus waves[J]. Geophysical Research Letters,2016-01-01,43(17).