Timescales of Birkeland Currents Driven by the IMF

Coxon, John, 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). pp. 7893-7901. ISSN 0094-8276

Geophysical Research Letters - 2019 - Coxon - Timescales of Birkeland Currents Driven by the IMF.pdf - Published Version
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Official URL: https://doi.org/10.1029/2018GL081658


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.

Item Type: Article
Additional Information: Funding Information: J.C.C. and R.C.F. were supported by Science and Technology Facilities Council (STFC) Ernest Rutherford grant ST/L002809/1 and Consolidated grant ST/R000719/1. R.M.S. and M.P.F. were supported by Natural Environment Research Council (NERC) grant NE/N01099X/1 and the SuperMAG EOF model was developed under NERC grant NE/J020796/1. R.C.F. was supported by STFC Ernest Rutherford Fellowship ST/K004298/2; S.D.B. was supported by STFC PhD studentship ST/M503794/1; A.W.S. was supported by a SEPnet PhD studentship; and D.K.W. was supported by NERC grant NE/N004051/1.
Uncontrolled Keywords: Birkeland currents, field-aligned currents, magnetopause, magnetotail, substorms, timescales
Subjects: F500 Astronomy
F600 Geology
F800 Physical and Terrestrial Geographical and Environmental Sciences
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 24 Feb 2022 10:14
Last Modified: 24 Feb 2022 10:15
URI: http://nrl.northumbria.ac.uk/id/eprint/48533

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