Julien Aubert, CNRS, IPG Paris

I am a CNRS senior researcher working at the Institut de Physique du Globe de Paris (IPGP), within the Geological Fluid Dynamics team. 

I am interested in the interpretation of the geomagnetic signal emanating from Earth’s liquid outer core. Over a broad range of space and time scales, this signal is a powerful probe for investigating the structure, dynamics and geological history of our planet. Understanding the geodynamo is an outstanding fundamental challenge of Physical Sciences as well as Earth Sciences. 

To this end I develop and use direct numerical computer simulations of the dynamo process, as well as data assimilation algorithms aiming at forecasting the future evolution of the geomagnetic field. This has important societal impacts as the geomagnetic field interacts with life on Earth and with human technological activities.


May 2019

Advanced geodynamo simulations at high resolution are obtained from previous approximated low-resolution cases. This ‘upsizing’ procedure does not perturb the leading-order dynamical characteristics of the previously obtained solutions, and enables an exploration of the properties of magnetohydrodynamic turbulence in the geodynamo. 

Aubert, J.: Approaching Earth’s core conditions in high resolution geodynamo simulations, Geophysical Journal International 219 S1, S137-S151, 2019, doi: 10.1093/gji/ggz232.

April 2019

The Earth’s magnetic field experiences unpredictable, rapid, and intense anomalies that are known as geomagnetic jerks. The mechanisms behind this phenomenon had remained a mystery until advanced numerical geodynamo simulations could simulate the rapid hydromagnetic wave dynamics that causes these anomalies. This research was published in Nature Geoscience on 22 April 2019.

Aubert, J. and Finlay, C.C.: Geomagnetic jerks and rapid hydromagnetic waves focusing at Earth’s core surface, Nature Geoscience 12, 393-398, 2019, doi: 10.1038/s41561-019-0355-1

February 2017

A new theory has been formulated to link the conditions of current numerical geodynamo models to those of the geodynamo. A theoretical ‘path’ in parameter space is described between the two sets of conditions, and explored up to its half using approximated numerical simulations. This new generation of numerical geodynamo models enters a regime close to Earth’s core conditions that was previously out of numerical reach. 

Aubert, J., Gastine, T., and Fournier, A.: Spherical convective dynamos in the rapidly rotating asymptotic regime, J. Fluid. Mech. 813, 558-593, 2017, doi: 10.1017/jfm.2016.789