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Timescales for the penetration of IMF By into the Earth's magnetotail

Browett, S.D., Fear, R.C., Grocott, A. and Milan, S.E. (2017) Timescales for the penetration of IMF By into the Earth's magnetotail Journal of Geophysical Research: Space Physics, 122, pp. 579-593. (doi:10.1002/2016JA023198).

Record type: Article


Previous studies have shown there is a correlation between the By component of the interplanetary magnetic field (IMF) and the By component observed in the magnetotail lobe and in the plasma sheet. However, studies of the effect of IMF By on several magnetospheric processes have indicated that the By component in the tail should depend more strongly on the recent history of the IMF By rather than on the simultaneous measurements of the IMF. Estimates of this timescale vary from ?15 minutes to ?4 hours. We present a statistical study of how promptly the IMF By component is transferred into the neutral sheet, based on Cluster observations of the neutral sheet from 2001 to 2008, and solar wind data from the OMNI database. 5982 neutral sheet crossings during this interval were identified, and starting with the correlation between instantaneous measurements of the IMF and the magnetotail (recently reported by Cao et al. [2014]), we vary the time delay applied to the solar wind data. Our results suggest a bimodal distribution with peaks at ?1.5 and ?3 hours. The relative strength of each peak appears to be well controlled by: the sign of the IMF Bz component with peaks being observed at 1 hour of lag time for southward IMF and up to 5 hours for northward IMF conditions, and the magnitude of the solar wind velocity with peaks at 2 hours of lag time for fast solar wind and 4 hours for slow solar wind conditions.

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Accepted/In Press date: 17 November 2016
e-pub ahead of print date: 22 November 2016
Published date: 23 January 2017
Organisations: Astronomy Group


Local EPrints ID: 404300
ISSN: 2169-9380
PURE UUID: 9a3db012-82c1-44b3-835f-cc714c411930
ORCID for R.C. Fear: ORCID iD

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Date deposited: 05 Jan 2017 14:22
Last modified: 23 Jul 2017 04:01

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Author: S.D. Browett
Author: R.C. Fear ORCID iD
Author: A. Grocott
Author: S.E. Milan

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