Modelling the Global Solar Corona III: Origin of the Hemispheric Pattern of Filaments

TL;DR

This study investigates the physical mechanisms behind the hemispheric pattern of filament chirality on the Sun using 3D simulations based on magnetic measurements, identifying key processes that produce the observed pattern.

Contribution

It identifies and describes the physical mechanisms responsible for the hemispheric pattern of filament chirality in solar corona simulations.

Findings

Differential rotation influences filament chirality.

Bipolar active region shapes affect filament patterns.

Skew evolution over days contributes to hemispheric pattern.

Abstract

We consider the physical origin of the hemispheric pattern of filament chirality on the Sun. Our 3D simulations of the coronal field evolution over a period of 6 months, based on photospheric magnetic measurements, were previously shown to be highly successful at reproducing observed filament chiralities. In this paper we identify and describe the physical mechanisms responsible for this success. The key mechanisms are found to be (1) differential rotation of north-south polarity inversion lines, (2) the shape of bipolar active regions, and (3) evolution of skew over a period of many days. As on the real Sun, the hemispheric pattern in our simulations holds in a statistical sense. Exceptions arise naturally for filaments in certain locations relative to bipolar active regions, or from interactions between a number of active regions.