DOI: 10.1002/2016GL070465
论文题名: Generation of He+ and O+ EMIC waves by the bunch distribution of O+ ions associated with fast magnetosonic shocks in the magnetosphere
作者: Lee K.H. ; Lee L.C.
刊名: Geophysical Research Letters
ISSN: 0094-8645
EISSN: 1944-8376
出版年: 2016
卷: 43, 期: 18 起始页码: 9406
结束页码: 9414
语种: 英语
英文关键词: fast shock
; helium and oxygen cyclotron waves
; oxygen bunch distribution
Scopus关键词: Cyclotrons
; Electron beams
; Fourier analysis
; Ions
; Cyclotron waves
; Dynamic pressure enhancements
; fast shock
; Frequency spectra
; Generation mechanism
; Ion cyclotrons
; Magnetosonic shocks
; Temperature anisotropy
; Magnetosphere
英文摘要: Electromagnetic ion cyclotron (EMIC) waves are often observed in the magnetosphere with frequency usually in the H+ and He+ cyclotron bands and sometimes in the O+ band. The temperature anisotropy, caused by injection of energetic ions or by compression of magnetosphere, can efficiently generate H+ EMIC waves, but not as efficient for He+ or O+ EMIC waves. Here we propose a new generation mechanism for He+ and O+ EMIC waves associated with weak fast magnetosonic shocks, which are observed in the magnetosphere. These shocks can be associated with either dynamic pressure enhancement or shocks in the solar wind and can lead to the formation of a “bunch” distribution in the perpendicular velocity plane of O+ ions. The O+ bunch distribution can excite strong He+ EMIC waves and weak O+ and H+ waves. The dominant He+ EMIC waves are strong in quasi-perpendicular propagation and show harmonics in frequency spectrum of Fourier analysis. The proposed mechanism can explain the generation and some observed properties of He+ and O+ EMIC waves in the magnetosphere. ©2016. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84992348923&doi=10.1002%2f2016GL070465&partnerID=40&md5=a77c05b498fb5dfa2a24f8fd81e1ea98
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9608
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: Institute of Earth Sciences, Academia Sinica, Nankang, Taiwan
Recommended Citation:
Lee K.H.,Lee L.C.. Generation of He+ and O+ EMIC waves by the bunch distribution of O+ ions associated with fast magnetosonic shocks in the magnetosphere[J]. Geophysical Research Letters,2016-01-01,43(18).