Dr Stefano Maffei

Profile

Research interests

My ongoing research goal is to infer the dynamics of the Earth’s core and of the fluid interiors of other planets in the solar system. Currently my research is focused on the Earth’s outer core and on the geomagnetic field.

My main tools are numerical models that can access the extreme parameter regimes that characterize the geophysical and astrophysical reality. These models are based on the overwhelming importance of rotation over all other forces (in particular viscosity) that act on the system. The development of these models (commonly known as QG, quasi- geostrophic) allows us to study the fluid layers of planets and stars in regimes that are currently out of reach of 3D numerical models and laboratory experiments.

SWIGS: Space Weather Impact on Ground Systems

At the University of Leeds I am involved in the SWIGS project. Goal of the project is to understand, predict and mitigate the impact of severe space weather events (caused by intense solar activity) on ground systems such as pipelines, electric power grids and rail networks. At the University of Leeds I aim at producing extreme forecasts of the geomagnetic field, with the purpose of developing worst-case scenarios under which the impact of geomagnetic storms at the surface are the most disrupting. This work is performed in collaboration with Dr. Phil Livermore and Dr. Jon Mound.

Predicting the speed of geomagnetic reversals

The same technique is used to answer the question: in how much time does the geomagnetic field switch polarity during a reversal? Present estimates suggest timescales of millennia, but some observsatsional studies point at much shorter times (decades-to-centuries). I aim at providing a lower bound (energetically motivated) for these timescales. Sam Greenwood is contributing to this study.

Quasi-geostrophic convection

In collaboration with Prof. Michael Calkins and Prof. Keith Julien I am studying thermal convection and magnetoconvection using asymptotic models derived under the assumptions of rapid rotation. These models allow us to reach parameter regimes that are relevant to geo- and astrophysical settings, something that cannot yet be done with traditional numerical models. The main focus is on the effect of an imposed magnetic field and of the material properties of the fluid in the formation of coherent structures.

Columnar models of the Earth’s oute core

In spherical geometries, quasi-geostrophic models have not yet been rigorously derived. However, they suggest that motions in the Earth’s outer core takes the shape of columns, aligned along the direction of the rotation axis. Ultimate purpose of this project (in collaboration with Prof. Andrew Jackson) is the incorporation of a columnar model in a geomagnetic data assimilation system that will deliver an unprecedented picture of the dynamics inside the Earth’s core. This tool will also produce a forecast for the magnetic field that will be valid for the next 50-100 years.