Thirty-Year Period in Secular Variation of the Main Geomagnetic Field
First published: 2022
Brief summary
Identifies a ~30-year periodic feature in the secular variation of Earth's main magnetic field, alongside known longer components: a 7000-year dipole axis rotation and 1800-year non-dipole westward drift cycle.
Article
Thirty-Year Period in Secular Variation of the Main Geomagnetic Field is a preprint published by arXiv in 2022. It identifies a ~30-year periodic feature in the secular variation of Earth's main magnetic field, alongside known longer components: a 7000-year dipole axis rotation and 1800-year non-dipole westward drift cycle.
The analysis focuses on ~30 years (secular variation), 7000 years (dipole axis rotation, ~0.05 deg/yr), 1800 years (non-dipole westward drift, 0.2 deg/yr). The data source is IGRF geomagnetic field models. This gives the cycle claim a specific numerical and evidential setting rather than presenting periodicity only as a visual impression.
The article reports the following result: The dipole axis rotates around the geographic axis at a rate of about 0.05 degrees per year, showing a 7000-year period, while the non-dipole field drifts westward and will take 1800 years for a complete round. The interpretation is strongest when measurement uncertainty, nonlinear dynamics, boundary conditions and alternative physical mechanisms are tested explicitly.
For cycles researchers, the article brings together geomagnetic secular variation, 30-year cycle, dipole rotation, westward drift. It is relevant to physical and geophysical systems in which oscillation, reversal, recurrence and nonlinear dynamics must be distinguished from random variability.
Because it is a preprint, the work should be read alongside later peer-reviewed publications and independent replications. It remains useful because the proposed cycle, dataset and analytical approach are stated clearly enough to be scrutinised.
Source details and credits
- Source / publisher: arXiv
- Source type: Preprint
- URL type: PDF
- Credits: arXiv
- URL: https://arxiv.org/pdf/2209.06486