DOI: 10.1002/2015GL065776
论文题名: Birkeland current effects on high-latitude ground magnetic field perturbations
作者: Laundal K.M. ; Haaland S.E. ; Lehtinen N. ; Gjerloev J.W. ; Østgaard N. ; Tenfjord P. ; Reistad J.P. ; Snekvik K. ; Milan S.E. ; Ohtani S. ; Anderson B.J.
刊名: Geophysical Research Letters
ISSN: 0094-9440
EISSN: 1944-9171
出版年: 2015
卷: 42, 期: 18 起始页码: 7248
结束页码: 7254
语种: 英语
英文关键词: Birkeland currents
; ground magnetic field
; ionospheric convection
; ionospheric currents
; seasonal differences
Scopus关键词: Magnetic fields
; Magnetism
; Curl-free components
; Current distribution
; Divergence-free components
; Ionospheric convection
; Ionospheric current
; Magnetic field perturbations
; Magnetic perturbation
; Seasonal differences
; Magnetic field effects
; convection
; current velocity
; dark
; ionosphere
; latitude
; magnetic field
; perturbation
英文摘要: Magnetic perturbations on ground at high latitudes are directly associated only with the divergence-free component of the height-integrated horizontal ionospheric current, J,df. Here we show how J,df can be expressed as the total horizontal current J minus its curl-free component, the latter being completely determined by the global Birkeland current pattern. Thus, in regions where J=0, the global Birkeland current distribution alone determines the local magnetic perturbation. We show with observations from ground and space that in the polar cap, the ground magnetic field perturbations tend to align with the Birkeland current contribution in darkness but not in sunlight. We also show that in sunlight, the magnetic perturbations are typically such that the equivalent overhead current is antiparallel to the convection, indicating that the Hall current system dominates. Thus, the ground magnetic field in the polar cap relates to different current systems in sunlight and in darkness. © 2015 American Geophysical Union. All Rights Reserved. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945492985&doi=10.1002%2f2015GL065776&partnerID=40&md5=cec5d6bbbedd50ac11a82213066e346f
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/9055
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: Birkeland Centre for Space Science, University of Bergen, Bergen, Norway
Recommended Citation:
Laundal K.M.,Haaland S.E.,Lehtinen N.,et al. Birkeland current effects on high-latitude ground magnetic field perturbations[J]. Geophysical Research Letters,2015-01-01,42(18).