The University of Southampton
University of Southampton Institutional Repository

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).

Record type: Article


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.

PDF Fear_etal_2014_preprint.pdf - Accepted Manuscript
Download (3MB)

More information

Accepted/In Press date: 19 November 2014
Published date: 19 December 2014
Organisations: Astronomy Group


Local EPrints ID: 377292
ISSN: 0036-8075
PURE UUID: d46bbb5d-ca60-41ca-9e59-04957f8ed8db
ORCID for R.C. Fear: ORCID iD

Catalogue record

Date deposited: 21 May 2015 14:18
Last modified: 17 Jul 2017 21:02

Export record



Author: R.C. Fear ORCID iD
Author: S.E. Milan
Author: R. Maggiolo
Author: A.N. Fazakerley
Author: I. Dandouras
Author: S.B. Mende

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton:

ePrints Soton supports OAI 2.0 with a base URL of

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.