Global-scale wreath-building dynamos in stellar convection zones

TL;DR

This paper investigates how rapidly rotating stars generate large-scale magnetic wreaths in their convection zones using 3-D MHD simulations, revealing that such structures are common and do not require tachoclines.

Contribution

It demonstrates the formation of global-scale magnetic wreaths in stellar convection zones across various rotation rates, challenging the necessity of tachoclines for organized dynamo action.

Findings

Wreath-like magnetic structures form in rapidly rotating stellar convection zones.

These dynamos exhibit quasi-cyclic polarity reversals.

Wreaths are most prominent at higher rotation rates.

Abstract

When stars like our Sun are young they rotate rapidly and are very magnetically active. We explore dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical harmonic (ASH) code. The magnetic fields built in these dynamos are organized on global-scales into wreath-like structures that span the convection zone. Wreath-building dynamos can undergo quasi-cyclic reversals of polarity and such behavior is common in the parameter space we have been able to explore. These dynamos do not appear to require tachoclines to achieve their spatial or temporal organization. Wreath-building dynamos are present to some degree at all rotation rates, but are most evident in the more rapidly rotating simulations.