Large Scale Properties of Tilt of Sunspot Groups and Joy's Law Near The Solar Equator

TL;DR

This paper investigates the physical mechanisms behind sunspot tilt angles near the solar equator, emphasizing the role of Coriolis forces and magnetic helicity balance over five solar cycles.

Contribution

It introduces a physical model explaining sunspot tilt formation based on magnetic helicity and Coriolis effects, extending previous models to multiple solar cycles.

Findings

Tilt angles vary with latitude and solar cycle phase.

The model aligns with observed Joy's law near the solar equator.

Sunspot tilt dynamics are influenced by large-scale magnetic helicity balance.

Abstract

We present a physical mechanism of formation of tilt angles of sunspots due to the process of formation of active regions below the solar photosphere. The contribution of Coriolis force factors on large-scale flows of super-granular convection in turbulent media has been investigated in details. On the basis of earlier works by Kleeorin et al. (2016) and Safiullin et al. (2018) we give physical estimates of orders of magnitude of the effect and estimate the tilt angles near the solar equator, in the "Royal" zone of solar activity. The above model is based on the balance of the small-scale and large scale magnetic helicities and describes in details the sunspot formation process over the last five solar cycles (since 1964). We adopt this model for a wider class of manifestations of solar activity. We present latitudinal dependence of the mean tilt on these five solar cycles and time-latitudinal diagrams over a limited range of latitudes and phases of the solar cycle.