Timescales of dayside and nightside field-aligned current response to changes in solar wind-magnetosphere coupling
Timescales of dayside and nightside field-aligned current response to changes in solar wind-magnetosphere coupling
Principal component analysis is performed on Birkeland or field-aligned current (FAC) measurements from the Active Magnetosphere and Planetary Electrodynamics Response Experiment, to determine the response of dayside and nightside FACs to reversals in the orientation of the interplanetary magnetic field (IMF) and the occurrence of substorms. Dayside FACs respond promptly to changes in IMF BY, but the nightside response is delayed by up to an hour and can take up to 4 hr to develop fully, especially during northward IMF. Nightside FAC asymmetries grow during substorm growth phase when the IMF has a significant BY component, and also promptly at substorm onset. Our findings suggest that magnetotail twisting and/or BY penetration into the magnetotail, due to subsolar reconnection with east-west orientated IMF, are the main cause of these nightside FAC asymmetries and that asymmetries also arise due to magnetotail reconnection of these twisted field lines.
currents, ionosphere, magnetosphere
Milan, Stephen E.
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Carter, Jennifer Alyson
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Sangha, Harneet
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Laundal, Karl M.
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Østgaard, Nikolai
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Tenfjord, Paul
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Reistad, Jone Peter
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Snekvik, Kristian
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Coxon, John C.
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Korth, Haje
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Anderson, Brian J.
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Milan, Stephen E.
b6dd5367-b0c4-4f30-953a-f2d13078d656
Carter, Jennifer Alyson
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Sangha, Harneet
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Laundal, Karl M.
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Østgaard, Nikolai
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Tenfjord, Paul
22f4480d-a8ad-4e90-9511-372b0284d92e
Reistad, Jone Peter
d94d8c8f-0372-467b-a939-158394bf264b
Snekvik, Kristian
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Coxon, John C.
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Korth, Haje
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Anderson, Brian J.
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Milan, Stephen E., Carter, Jennifer Alyson, Sangha, Harneet, Laundal, Karl M., Østgaard, Nikolai, Tenfjord, Paul, Reistad, Jone Peter, Snekvik, Kristian, Coxon, John C., Korth, Haje and Anderson, Brian J.
(2018)
Timescales of dayside and nightside field-aligned current response to changes in solar wind-magnetosphere coupling.
Journal of Geophysical Research: Space Physics.
(doi:10.1029/2018JA025645).
Abstract
Principal component analysis is performed on Birkeland or field-aligned current (FAC) measurements from the Active Magnetosphere and Planetary Electrodynamics Response Experiment, to determine the response of dayside and nightside FACs to reversals in the orientation of the interplanetary magnetic field (IMF) and the occurrence of substorms. Dayside FACs respond promptly to changes in IMF BY, but the nightside response is delayed by up to an hour and can take up to 4 hr to develop fully, especially during northward IMF. Nightside FAC asymmetries grow during substorm growth phase when the IMF has a significant BY component, and also promptly at substorm onset. Our findings suggest that magnetotail twisting and/or BY penetration into the magnetotail, due to subsolar reconnection with east-west orientated IMF, are the main cause of these nightside FAC asymmetries and that asymmetries also arise due to magnetotail reconnection of these twisted field lines.
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Milan_et_al-2018-Journal_of_Geophysical_Research%3A_Space_Physics
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Accepted/In Press date: 14 July 2018
e-pub ahead of print date: 23 July 2018
Keywords:
currents, ionosphere, magnetosphere
Identifiers
Local EPrints ID: 423283
URI: http://eprints.soton.ac.uk/id/eprint/423283
ISSN: 2169-9380
PURE UUID: b50fe72c-57a4-4d02-972f-534c304fdcba
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Date deposited: 20 Sep 2018 16:30
Last modified: 15 Mar 2024 21:44
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Contributors
Author:
Stephen E. Milan
Author:
Jennifer Alyson Carter
Author:
Harneet Sangha
Author:
Karl M. Laundal
Author:
Nikolai Østgaard
Author:
Paul Tenfjord
Author:
Jone Peter Reistad
Author:
Kristian Snekvik
Author:
Haje Korth
Author:
Brian J. Anderson
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