Rapid Variations of Earth's Core Magnetic Field

TL;DR

This paper investigates rapid variations in Earth's core magnetic field using ground and satellite data, analyzing their structure, properties, and potential wave origins to better understand core dynamics.

Contribution

It introduces methods to identify and characterize fast magnetic field variations at Earth's surface and boundary, linking them to core wave phenomena.

Findings

Fast variations are observed in ground and satellite data.

Properties of variations at the core-mantle boundary are characterized.

Possible wave types causing variations are identified.

Abstract

Evidence of fast variations in the Earth's core field are seen both in magnetic observatory and satellite records. We present here how they have been identified at the Earth's surface from ground-based observatory records and how their spatio-temporal structure is now characterised by satellite data. It is shown how their properties at the core mantle boundary are extracted through localised and global modelling processes, paying particular attention to their time scales. Finally are listed possible types of waves in the liquid outer core, together with their main properties, that may give rise to these observed fast variations.