Direct observation of closed magnetic flux trapped in the high-latitude magnetosphere

Fear, R.C., Milan, S.E., Maggiolo, R., Fazakerley, A.N., Dandouras, I. and Mende, S.B. (2014) Direct observation of closed magnetic flux trapped in the high-latitude magnetosphere Science, 346, (6216), pp. 1506-1510. (doi:10.1126/science.1257377).


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The structure of Earth’s magnetosphere is poorly understood when the interplanetary magnetic field is northward. Under this condition, uncharacteristically energetic plasma is observed in the magnetotail lobes, which is not expected in the textbook model of the magnetosphere. Using satellite observations, we show that these lobe plasma signatures occur on high-latitude magnetic field lines that have been closed by the fundamental plasma process of magnetic reconnection. Previously, it has been suggested that closed flux can become trapped in the lobe and that this plasma-trapping process could explain another poorly understood phenomenon: the presence of auroras at extremely high latitudes, called transpolar arcs. Observations of the aurora at the same time as the lobe plasma signatures reveal the presence of a transpolar arc. The excellent correspondence between the transpolar arc and the trapped closed flux at high altitudes provides very strong evidence of the trapping mechanism as the cause of transpolar arcs.

Item Type: Article
Digital Object Identifier (DOI): doi:10.1126/science.1257377
ISSNs: 0036-8075 (print)
Subjects: Q Science > QC Physics
Organisations: Astronomy Group
ePrint ID: 377292
Date :
Date Event
19 November 2014Accepted/In Press
19 December 2014Published
Date Deposited: 21 May 2015 14:18
Last Modified: 17 Apr 2017 06:07
Further Information:Google Scholar

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