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.



Congratulations to Dr. Tobias Schwaiger for a great PhD. defense, reflecting a great manuscript and work. Tobias has been supervised by Thomas Gastine and myself. He systematically studied the force balance in numerical dynamos throughout the accessible parameter space, and the links between the length scales of the solution and this force balance. Two papers have been published from this work:

Schwaiger, T., Gastine, T. and Aubert, J.: Relating force balances and flow length scales in geodynamo simulations, Geophys. J. Int., 2020, doi: 10.1093/gji/ggaa545.

Schwaiger, T., Gastine, T., Aubert, J.: Force balance in numerical geodynamo simulations: a systematic study, Geophys. J. Int 219 S1, S101-S114, 2019, doi: 10.1093/gji/ggz192.

Congrats Tobias!

PhD. defense of Tobias Schwaier, november 23 2020

January 2020

Dynamical constraints on the leading-order ‘QG-MAC’ force balance expected in Earth’s core have been integrated into a geomagnetic inverse problem framwork, enabling a dynamically-consistent estimate of the fluid flow, density anomaly and magnetic field near the core surface from recent geomagnetic data. The technique also quantifies the consistency of this ‘QG-MAC’ balance with geomagnetic data. 

Aubert, J.: Recent geomagnetic variations and the force balance in Earth’s core, Geophys. J. Int. 221, 378-393, 2020, doi: 10.1093/gji/ggaa007.

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.