Unravelling the mystery of the Earth’s magnetic field
Univ. Grenoble Alpes/CNRS/IRD, ISTerre
F-38000 Grenoble, France
Slow convective motions in the liquid iron core of the Earth give birth to its magnetic field. How do these motions get organized under the combined effects of the Coriolis and Lorentz forces? Lab experiments reveal a peculiar behaviour. They also suggest that we need to reconsider what turbulence means in these conditions. Our better understanding of the dynamics of the core, and ever more precise observations have led to the recent discovery of a spectacular phenomenon: the propagation of torsional Alfve´n waves, which jerk the core every 3-4 years.
© European Physical Society, EDP Sciences, 2014