Magnetic field intensification by three-dimensional explosion process

TL;DR

This paper explores a three-dimensional magnetohydrodynamic process called magnetic flux explosion, which can intensify magnetic fields in the solar convection zone without relying solely on differential rotation, by converting convective potential energy into magnetic energy.

Contribution

It extends previous two-dimensional studies of flux tube explosion to three-dimensional simulations, demonstrating conditions for effective magnetic field intensification.

Findings

Large-scale perturbations lead to significant magnetic field amplification.

Small-scale perturbations cause flux sheets to rise, reducing amplification.

Three-dimensional effects are crucial for realistic modeling of flux explosion.

Abstract

We investigate an intensification mechanism for the magnetic field near the base of the solar convection zone that does not rely on differential rotation. Such mechanism in addition to differential rotation has been suggested by studies of flux emergence, which typically require field strength in excess of those provided by differential rotation alone. We study here a process in which potential energy of the superadiabatically stratified convection zone is converted into magnetic energy. This mechanism, know as explosion of magnetic flux tubes, has been previously studied in the thin flux tube approximation as well as two-dimensional MHD simulations, we expand the investigation to three-dimensional MHD simulations. Our main result is that enough intensification can be achieved in a three-dimensional magnetic flux sheet as long as the spatial scale of the imposed perturbation normal to the magnetic field is sufficiently large. When this spatial scale is small, the flux sheet tends to rise toward the surface, resulting in a significant decrease of the magnetic field amplification.