Thanks to the three satellites of the European Space Agency's Swarm Project, launched in 2013, whose objective is to measure and distinguish the different magnetic fields that are formed by the nucleus, the mantle, the crust, the oceans, the ionosphere and the terrestrial magnetosphere, it has been possible to identify real currents of iron fluids . They flow in the earth's core and, due to some characteristics, including speed, are compared to atmospheric currents called jet currents.
Jet currents. The main magnetic field of our planet is due to the ocean of superheated liquid iron that constitutes the great part of the external nucleus, which begins at about 2, 900 km of depth.Arrangement and different orbits of the Swarm satellites allow to reconstruct the evolution of the earth's magnetic field and what it produces. | ESA
The motions of this fluid in such an extreme environment for temperatures and pressures creates powerful electric currents which, in turn, generate the magnetic field that surrounds the entire Earth (and protects us from solar wind and cosmic radiation).
Thanks to the accurate measurements obtained by the Swarm satellites it was possible to distinguish with extreme precision the magnetism produced in the core from that of another origin. Thus, by monitoring the changes in the magnetic field produced by the nucleus, a group of researchers was able to understand how iron moves at such depths.
In a work published in Nature Geoscience (summary, in English) the geophysicists of the universities of Leeds (UK) and Copenhagen (Denmark) propose a model of the core of the Earth where there would be real jet-currents of molten material, which indeed recall the jet currents in the upper atmosphere.
Alaska and Siberia. Philip Livermore (Leeds), lead author of the study, underlines the importance of the work: «From the measurements of the Swarm satellites we acquired information on the dynamics of the earth's core as never before: for the first time we have detected the fast motions of the iron in the outer core, and we have understood the reasons for these currents ».The secondary magnet fields that form inside and outside the Earth make the study of the main magnetic field more complex. | ESA
The research has revealed that beneath Alaska and Siberia the liquid iron of the external nucleus moves at about 40 km a year, that is thousands of times more rapidly than the tectonic plates that make up the outer part of the planet . The jets are formed between two regions of the core, where the material moves as if it were squeezed, thus forming a jet.
It is very likely that at the base of all this there are significant variations in the magnetic field for different areas of the nucleus itself. According to the researchers, the identification of these currents is only the first of many surprises that the magnetic field of our planet could hold for us.