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Hints on the Multiscale Nature of Geomagnetic Field Fluctuations During Quiet and Disturbed Periods
Author(s) -
Santarelli L.,
De Michelis P.,
Consolini G.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028596
Subject(s) - earth's magnetic field , ionospheric dynamo region , quiet , ionosphere , geophysics , magnetosphere , physics , geomagnetic secular variation , magnetic field , ring current , current (fluid) , geomagnetic storm , atmospheric sciences , astronomy , quantum mechanics , thermodynamics
We analyze the geomagnetic data recorded at 78 stations from 13 to 31 March 2015. Using the empirical mode decomposition (EMD) method, we focus our attention on geomagnetic signal due to sources which are external to the Earth, that is, due to current systems flowing in the ionosphere and magnetosphere. We analyze the short timescale fluctuations ( τ < 200 min) of this magnetic signal, their dependence on magnetic latitude, magnetic local time, and geomagnetic activity. At high geomagnetic latitudes (>|60°|), these short timescale fluctuations constitute more than 30% of the external magnetic field. Their maximum contribution occurs along the auroral oval suggesting that they are mainly triggered by the ionospheric electric current systems active in these regions. A discussion of the relevance of these short timescale magnetic fluctuations to result in a more significant modeling and prediction of geomagnetically induced currents in the auroral zones is also provided.