The Nondipole Part of the Main Geomagnetic Field and the Large Scale Topographical Heterogeneities of the Core-Mantle Boundary

TL;DR

This paper investigates the nondipole component of Earth's main geomagnetic field and its relation to large-scale topographical heterogeneities at the core-mantle boundary, using satellite data and comparative analysis.

Contribution

It extends previous studies by analyzing the large-scale sources of the nondipole geomagnetic field and their connection to core-mantle boundary irregularities.

Findings

Large-scale heterogeneities influence the nondipole geomagnetic field.

Topographic irregularities may be linked to geomagnetic anomalies.

The study provides insights into the Earth's core-mantle boundary dynamics.

Abstract

Based on satellite data, both large and small-scale flows were identified on the core surface .At the same time, the observed rapid decrease in the dipole component of the main geomagnetic field does not find a satisfactory explanation. In the previous papers we carried out the comparative studies of the structure of the lowest mantle with the motion path of the small size current loops approximating the MGF's small-scale anomalies. The hypothesis was stated that heterogeneities in the lowest mantle structure and the topographic irregularities of the core-mantle boundary associated with ancient subduction zones is one of the primarily responsible for the small-scale vortices formation and the local MGF variation. In this paper, we carry out the analogous comparison for the large scale sources approximating the nondipole part of the geomagnetic field.