| DOI: | 10.1002/grl.50958
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| 论文题名: | Large flow shears around auroral beads at substorm onset |
| 作者: | Hosokawa K.; Milan S.E.; Lester M.; Kadokura A.; Sato N.; Bjornsson G.
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| 刊名: | Geophysical Research Letters
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| ISSN: | 0094-8528
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| EISSN: | 1944-8259
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| 出版年: | 2013
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| 卷: | 40, 期:19 | | 起始页码: | 4987
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| 结束页码: | 4991
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| 语种: | 英语
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| 英文关键词: | auroral beads
; auroral substorm
; field-aligned current
; ground-based radar
; ionospheric convection
; plasma instabilities
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| Scopus关键词: | auroral beads
; Field aligned currents
; Ground based radar
; Ionospheric convection
; Substorms
; Electric fields
; Electrodynamics
; Electromagnetic fields
; Magnetohydrodynamics
; Magnetosphere
; Plasma flow
; Plasma stability
; Radar
; Radar measurement
; aurora
; electric field
; electrodynamics
; flow velocity
; radar
; shear flow
; spatial resolution
; spatiotemporal analysis
; Ambystoma tigrinum stebbensi virus
|
| 英文摘要: | We present a fine-scale electrodynamic structure behind the auroral beads observed immediately before substorm onset, as inferred from high spatial and temporal resolution measurements of substorm with an all-sky TV camera (ATV) and a coherent high frequency radar of Super Dual Auroral Radar Network in Iceland. On the night of 24 September 2006, the ATV observed eastward propagating auroral beads in the initial brightening arc of a substorm just prior to the poleward expansion. During the sequential passage of the beads across the radar beams, the radar detected large velocity flow shears whose magnitude was in excess of 0.27 s-1. The observations suggest that flow shears were located very close to the center of the beads; thus, they corresponded to electric fields converging toward the beads, which is consistent with the existence of upward field-aligned currents (FACs) flowing out of the beads. The temporal and spatial resolutions of the current radar measurement were still insufficient for fully resolving the detailed electrodynamic structure behind the fast moving auroral beads. At least, however, we can suggest the existence of highly localized filamentary FAC structures behind the beads, which would be an important consequence of possible plasma instabilities operating in the M-I coupling region or near the equatorial plane of the magnetosphere. Key Points High spatiotemporal resolution radar measurement of initial brightening arc Strong velocity flow shears were identified in the vicinity of the auroral beads Highly-localized filamentary FAC structures exist behind auroral beads ©2013. American Geophysical Union. All Rights Reserved. |
| URL: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884798130&doi=10.1002%2fgrl.50958&partnerID=40&md5=0df963a1d62a0f031b0d73ce2c70f73e
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| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/5792
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| Appears in Collections: | 气候减缓与适应
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作者单位: | Department of Communication Engineering and Informatics, University of Electro-Communications, Tokyo, Japan
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| Recommended Citation: | |
Hosokawa K.,Milan S.E.,Lester M.,et al. Large flow shears around auroral beads at substorm onset[J]. Geophysical Research Letters,2013-01-01,40(19).
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