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Updated: Jul 9, 2026

Geomagnetic Field (Gmf) and Plant Evolution: Investigating the Effects of Gmf Reversal on Arabidopsis thaliana Development and Gene Expression

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Published on: November 30, 2015

Gravitational dynamos and the low-frequency geomagnetic secular variation.

¹Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, MD 21218, USA. olson@jhu.edu

Proceedings of the National Academy of Sciences of the United States of America

|December 1, 2007

Summary

Numerical dynamo models reveal that gravitational convection drives Earth's geomagnetic secular variation. Increasing convection leads to more frequent polarity reversals and dipole changes, mimicking the geomagnetic field.

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Geomagnetic Field (Gmf) and Plant Evolution: Investigating the Effects of Gmf Reversal on Arabidopsis thaliana Development and Gene Expression

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Magnetically Induced Rotating Rayleigh-Taylor Instability

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Published on: March 3, 2017

Area of Science:

Geophysics
Computational physics
Earth science

Background:

The geomagnetic field's low-frequency secular variation originates from complex processes within Earth's core.
Numerical dynamo models are crucial for understanding the geodynamo and its behavior.

Purpose of the Study:

To investigate the sources of low-frequency geomagnetic secular variation using self-sustaining numerical dynamos.
To explore the relationship between convection intensity and magnetic field dynamics in gravitational dynamo models.

Main Methods:

Utilized self-sustaining numerical dynamo simulations.
Employed gravitational dynamo models powered by compositional convection in a rotating fluid shell.
Analyzed magnetic field behavior across various Rayleigh numbers.

Main Results:

Observed distinct regimes: steady dipoles, chaotic nonreversing, and chaotic reversing dipoles with increasing Rayleigh number.
Found that higher Rayleigh numbers decrease dipole strength and dipolarity but increase variability, tilt angle, and reversal frequency.
Chaotic dynamos exhibit secular variation comparable to Earth's geomagnetic field in structure, statistics, and reversal frequency.

Conclusions:

Gravitational dynamo models successfully replicate key features of Earth's geomagnetic field, including secular variation and polarity reversals.
The Lorentz force drives magnetic variability, characterized by an inverse correlation between magnetic and kinetic energy.
Constant energy dissipation theory explains phenomena like dipole drift, reversals, and excursions.