DOI: 10.1029/2018JA025409
Scopus记录号: 2-s2.0-85050262081
论文题名: Swarm Satellite and EISCAT Radar Observations of a Plasma Flow Channel in the Auroral Oval Near Magnetic Midnight
作者: Aikio A.T. ; Vanhamäki H. ; Workayehu A.B. ; Virtanen I.I. ; Kauristie K. ; Juusola L. ; Buchert S. ; Knudsen D.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 6 起始页码: 5140
结束页码: 5158
语种: 英语
英文关键词: auroral oval
; EISCAT radar
; ionospheric currents
; ionospheric electric field
; plasma flow
; Swarm satellite
英文摘要: We present Swarm satellite and EISCAT radar observations of electrodynamical parameters in the midnight sector at high latitudes. The most striking feature is a plasma flow channel located equatorward of the polar cap boundary within the dawn convection cell. The flow channel is 1.5° wide in latitude and contains southward electric field of 150 mV/m, corresponding to eastward plasma velocities of 3,300 m/s in the F-region ionosphere. The theoretically computed ion temperature enhancement produced by the observed ion velocity is in accordance with the measured one by the EISCAT radar. The total width of the auroral oval is about 10° in latitude. While the poleward part is electric field dominant with low conductivity and the flow channel, the equatorward part is conductivity dominant with at least five auroral arcs. The main part of the westward electrojet flows in the conductivity dominant part, but it extends to the electric field dominant part. According to Kamide and Kokubun (1996), the whole midnight sector westward electrojet is expected to be conductivity dominant, so the studied event challenges the traditional view. The flow channel is observed after substorm onset. We suggest that the observed flow channel, which is associated with a 13-kV horizontal potential difference, accommodates increased nightside plasma flows during the substorm expansion phase as a result of reconnection in the near-Earth magnetotail. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113753
Appears in Collections: 气候减缓与适应
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作者单位: Ionospheric Physics Unit, University of Oulu, Oulu, Finland; International Center for Space Weather Science and Education, Kyushu University, Fukuoka, Japan; Finnish Meteorological Institute, Helsinki, Finland; Swedish Institute of Space Physics, Uppsala, Sweden; Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada
Recommended Citation:
Aikio A.T.,Vanhamäki H.,Workayehu A.B.,et al. Swarm Satellite and EISCAT Radar Observations of a Plasma Flow Channel in the Auroral Oval Near Magnetic Midnight[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(6)