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Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/8684

Authors: Qamili, E.*
De Santis, A.*
Isac, A.*
Mandea, M.*
Duka, B.*
Simonyan, A.*
Title: Geomagnetic jerks as chaotic fluctuations of the Earth’s magnetic field
Title of journal: Geochemistry, Geophysics, Geosystems
Series/Report no.: / 14 (2013)
Publisher: American Geophysical Union
Issue Date: 12-Apr-2013
DOI: 10.1029/2012GC004398
Keywords: geomagnetic field
geomagnetic jerks
ergodicity
chaos
Abstract: The geomagnetic field is chaotic and can be characterized by a mean exponential time scale<t>after which it is no longer predictable. It is also ergodic, so time analyses can substitute the more difficult phase space analyses. Taking advantage of these two properties of the Earth’s magnetic field, a scheme of processing global geomagnetic models in time is presented, to estimate fluctuations of the time scale t. Here considering that the capability to predict the geomagnetic field is reduced over periods of geomagnetic jerks, we propose a method to detect these events over a long time span. This approach considers that epochs characterized by relative minima of fluctuations in time scale t, i.e., those periods when a geomagnetic field is less predictable, are possible jerk occurrence dates. We analyze the last 400 years of the geomagnetic field (covered by the Gufm1 model) to detect minima of fluctuations, i.e., epochs characterized by low values of the time scale.Most of the well known jerks are confirmed through this method and a few others have been suggested. Finally, we also identify some short periods when the field is less chaotic (more predictable) than usual, naming these periods as steady state geomagnetic regime, to underline their opposite behavior with respect to jerks.
Appears in Collections:04.05.02. Geomagnetic field variations and reversals
Papers Published / Papers in press

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