Axisymmetric Magnetic Fields can be Stably Generated by Simple Convection

Abstract

Researchers have struggled to understand the mechanism underlying the formation of celestial magnetic fields. The concept that complex convection is necessary to generate a magnetic field in some studies, including Cowling’s theorem, constrains research. Research in this field could progress through the discovery of a simple mechanism. This paper addresses simple axisymmetric poloidal convection and magnetic fields. The problem arises when rigorously deriving the electromagnetic induction equations. This is explained by comparison using Cowling’s theorem as an example. Cowling’s theory omits certain elements from this equation. However, it was found that these elements are the very essence of axisymmetric magnetic field generation. In other words, the meaning of Cowling’s theorem is reversed. This is a novel concept. As a result, even under simple axisymmetric convection, the possibility of generating axisymmetric magnetic fields is demonstrated. These findings will contribute to further elucidating the mechanism of magnetic field formation.