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Projects

Measuring, modelling and predicting the hole in the Earth’s magnetic field

This Project has been filled

Background

The geomagnetic field is a fundamental component of Earth. Wrapping around our planet like an invisible
force-field, it protects life from harmful solar radiation and influences the impacts of space weather on modern
technologies, such as satellites and electrical power grids. Yet similar to the ozone hole in the atmosphere,
there is a weakspot in this shield, termed the south Atlantic anomaly (SAA). The Earth’s magnetic field is
dynamic and changes on yearly to decadal timescales, and unlike the ozone hole the SAA is currently
growing. Satellites that fly through this region of weakened field experience electronic upsets (see figure).
From 1999 satellites have continuously measured the Earth’s geomagnetic field, the most recent of which is
ESA satellite mission Swarm, launched in 2013. These and future monitoring, alongside both recent and
historical ground-based measurements, will allow a detailed study of the SAA, including modelling of its origin
deep within the Earth’s core and its space weather implications.

Left: the Earth’s magnetic field acts as a shield from harmful solar radiation. Right: map of temporary
electronic failures (single event upsets (SEUs), white dots) on the three Swarm satellites, 2014-2019, which
occur primarily in the SAA (shown as blue area) but also in auroral regions.

Objectives

  1. To map the SAA both in terms of magnetic field strength, observations of energetic particles (e.g.
    those causing the SEUs) and simple models of the positioning of the Earth’s radiation belts which
    transport these charged particles.
  2. To create new dynamical models of the Earth’s liquid core consistent with geomagnetic observations,
    exploiting the magnetic field gradient measurements made possible by simultaneous measurement
    using Swarm’s trio of spacecraft. These new models will be focussed on understanding how the SAA
    arises, and will be used along with machine learning, to assess its future structure.
  3. To forecast the structure of the magnetic field and the SAA, and thereby assess its space weather
    implications such as the geometry of the radiation belts and their impact on spacecraft.

Requirements

We seek a highly motivated candidate with a strong background in mathematics, physics, computation,
geophysics or another highly numerate discipline. Knowledge of geomagnetism is not required, and training
will be given in all aspects of the PhD.

Further reading

Pavón-Carrasco, F. J., & De Santis, A. (2016). The South Atlantic Anomaly: The Key for a Possible
Geomagnetic Reversal. Frontiers in Earth Science, 4(61), 1738–9.
Casadio, S., & Arino, O. (2011). Monitoring the South Atlantic Anomaly using ATSR instrument series.
Advances in Space Research, 48(6), 1056–1066.