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Timescales of Birkeland currents driven by the IMF

Timescales of Birkeland currents driven by the IMF
Timescales of Birkeland currents driven by the IMF
We obtain current densities from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE), alongside By and Bz from the Interplanetary Magnetic Field (IMF) for March 2010. For each AMPERE spatial coordinate, we cross‐correlate current density with By and Bz, finding the maximum correlation for lags up to 360 min. The patterns of maximum correlation contain large‐scale structures consistent with the literature. For the correlation with By, the lags on the dayside are 10 min at high latitudes but up to 240 min at lower latitudes. Lags on the nightside are 90–150 min. For Bz, the shortest lags on the dayside are 10–20 min; on the equatorward edge of the current oval, 60–90 min; and on the nightside, predominantly 90–150 min. This novel approach enables us to see statistically the timescales on which information is electrodynamically communicated to the ionosphere after magnetic field lines reconnect on the dayside and nightside.
0094-8276
1-9
Coxon, John C.
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Shore, Robert M.
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Freeman, Mervyn P.
dc974e00-a73d-4d41-a2a8-3c5aebd7a5b5
Fear, Robert C.
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Browett, Stephen D.
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Smith, Andrew W.
f719dbf6-612c-4ecb-9ec8-ae0ac74928eb
Whiter, Daniel K.
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Anderson, Brian J.
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Coxon, John C.
566baea5-6a30-4855-bde3-a09c115efde4
Shore, Robert M.
f4c8cc35-3ff0-40ee-9448-207292309c6a
Freeman, Mervyn P.
dc974e00-a73d-4d41-a2a8-3c5aebd7a5b5
Fear, Robert C.
8755b9ed-c7dc-4cbb-ac9b-56235a0431ab
Browett, Stephen D.
27588ce7-285d-43e7-97a6-7640936ac703
Smith, Andrew W.
f719dbf6-612c-4ecb-9ec8-ae0ac74928eb
Whiter, Daniel K.
9a30d7b6-ea41-44fb-bd52-3ff1964eca5c
Anderson, Brian J.
83afb235-d7a7-4c17-8151-f32fee334291

Coxon, John C., Shore, Robert M., Freeman, Mervyn P., Fear, Robert C., Browett, Stephen D., Smith, Andrew W., Whiter, Daniel K. and Anderson, Brian J. (2019) Timescales of Birkeland currents driven by the IMF. Geophysical Research Letters, 46 (14), 1-9. (doi:10.1029/2018GL081658).

Record type: Article

Abstract

We obtain current densities from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE), alongside By and Bz from the Interplanetary Magnetic Field (IMF) for March 2010. For each AMPERE spatial coordinate, we cross‐correlate current density with By and Bz, finding the maximum correlation for lags up to 360 min. The patterns of maximum correlation contain large‐scale structures consistent with the literature. For the correlation with By, the lags on the dayside are 10 min at high latitudes but up to 240 min at lower latitudes. Lags on the nightside are 90–150 min. For Bz, the shortest lags on the dayside are 10–20 min; on the equatorward edge of the current oval, 60–90 min; and on the nightside, predominantly 90–150 min. This novel approach enables us to see statistically the timescales on which information is electrodynamically communicated to the ionosphere after magnetic field lines reconnect on the dayside and nightside.

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Coxon et al 2019 Geophysical Research Letters - Version of Record
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Submitted date: 17 December 2018
Accepted/In Press date: 21 February 2019
e-pub ahead of print date: 24 July 2019

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Local EPrints ID: 433155
URI: https://eprints.soton.ac.uk/id/eprint/433155
ISSN: 0094-8276
PURE UUID: 5ec240a8-3563-44c2-86bb-cfbfafaa96ca
ORCID for John C. Coxon: ORCID iD orcid.org/0000-0002-0166-6854
ORCID for Robert C. Fear: ORCID iD orcid.org/0000-0003-0589-7147
ORCID for Andrew W. Smith: ORCID iD orcid.org/0000-0001-7321-4331
ORCID for Daniel K. Whiter: ORCID iD orcid.org/0000-0001-7130-232X

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Date deposited: 09 Aug 2019 16:30
Last modified: 03 Dec 2019 01:43

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Contributors

Author: John C. Coxon ORCID iD
Author: Robert M. Shore
Author: Mervyn P. Freeman
Author: Robert C. Fear ORCID iD
Author: Stephen D. Browett
Author: Andrew W. Smith ORCID iD
Author: Brian J. Anderson

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