Geomagnetic field excursions: revealing the extreme states of Earth's outer core

Introduction

EXCURSION resolves around fundamental questions concerning the operational mechanism, causation, and predictability of the most frequent transitional events of the Earth's magnetic field.

Geomagnetic Excursions

Geomagnetic excursions are episodes of low field intensity globally with no complete polarity reversals but anomalous magnetic directions that do not reflect a dipolar field. They reduce the shielding against solar and cosmic radiation, thus triggering significant technological and potential environmental and climatic impacts.

Urgency of Study

Our understanding of geomagnetic excursions is severely limited. The urgency to study these events arises from several facts, including:

1. The substantial decrease in geomagnetic field strength over the past centuries.
2. Certain future events considering the dynamic nature of excursions.
3. Harmful effects on modern technology.

To advance in this subject, we must understand the core dynamics and global and regional characteristics of as many of these events as possible.

Project Focus

This project focuses on the geomagnetic excursions in the Brunhes Chron (past 780,000 years). I will build the first data-based model of the geomagnetic field over the Brunhes Chron, complemented with high-resolution reconstructions of excursions.

Methodology

These models will be assimilated into state-of-the-art 3D dynamo simulations to infer the excursional state of the core and geodynamo. Furthermore, novel machine learning methods will be applied to the new models to assess past field configurations that resemble the present day and identify common characteristics and potential precursors of the excursions.

Conclusion

This ground-breaking synthesis of multi-excursional events analyzed with data-based reconstructions, data assimilation by 3D numerical simulations, and machine learning techniques will create a holistic framework and will advance our knowledge beyond the current understanding of the Earth's outer core dynamics.