Origin of Joy's Law in the context of Near-Surface Convection on the Sun

TL;DR

This paper reviews observational results on Joy's law, a key property of solar active regions, and discusses its origin in near-surface convection, highlighting its importance for solar magnetic field dynamics.

Contribution

It synthesizes observational data on Joy's law's onset and contextualizes active region emergence as a passive near-surface process on the Sun.

Findings

Joy's law is crucial for solar magnetic field reversal.

Active region tilt angles are linked to near-surface convection.

Surface emergence processes are largely passive.

Abstract

Joy's law is a well-established statistical property of solar active regions that any theory of active region emergence must explain. This tilt angle of the active region away from an east-west alignment is a critical component for converting the toroidal magnetic field to poloidal magnetic field in some leading dynamo theories, and observations show they are important for the reversal of the sign of the global solar magnetic dipole. This review aims to synthesise observational results related to the onset of Joy's law, placing them within the broader context that describes active region emergence as a largely passive process occurring near the surface of the Sun.