DOI: 10.1002/2015GL063893
论文题名: The upstream-propagating Alfvénic fluctuations with power law spectra in the upstream region of the Earth's bow shock
作者: Wang X. ; Tu C. ; Wang L. ; He J. ; Marsch E.
刊名: Geophysical Research Letters
ISSN: 0094-9546
EISSN: 1944-9277
出版年: 2015
卷: 42, 期: 10 起始页码: 3654
结束页码: 3661
语种: 英语
英文关键词: Alfvén waves
; energetic particles
; solar wind
; turbulence
Scopus关键词: Ion beams
; Solar wind
; Turbulence
; Beam instability
; Dynamic equilibria
; Earth's bow shock
; Energetic ion events
; Energetic particles
; N-waves
; Power law spectrum
; Propagation direction
; Ions
; frequency-magnitude distribution
; outflow
; power law
; solar wind
; turbulence
; wave propagation
; wave-wave interaction
英文摘要: Based on theories, the beam instability induced by shock-accelerated ions can generate upstream-propagating Alfvén waves (UPAWs) with a power spectral bump near 0.03 Hz, while the nonlinear wave-wave interaction favors an inverse cascade to create a power law spectrum. Here we present the first observational evidence for the upstream-propagating Alfvénic fluctuations (UPAFs) with power law spectra. We utilize a new criterion to identify the upstream-propagating Alfvénic intervals: the propagation direction is opposite to that of solar wind strahl electron outflow. Besides 35 UPAWs, we find 47 UPAFs with power law spectra, and ∼47% of these UPAFs are associated with energetic ion events (>30 keV). These UPAWs and UPAFs are mostly observed in the slow solar wind. However, their occurrence rate and power behave differently in dependence on the radial distance from the Earth. These results provide new clues on understanding the dynamic equilibrium between the nonlinear inverse cascade and the linear ion beam instability. ©2015. American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84931563031&doi=10.1002%2f2015GL063893&partnerID=40&md5=b84246dd53ee60003c6966d703ac2d7f
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9161
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: School of Earth and Space Sciences, Peking University, Beijing, China
Recommended Citation:
Wang X.,Tu C.,Wang L.,et al. The upstream-propagating Alfvénic fluctuations with power law spectra in the upstream region of the Earth's bow shock[J]. Geophysical Research Letters,2015-01-01,42(10).