Avalanching together: A model for sympathetic flaring

TL;DR

This paper introduces a novel interconnected avalanche model to simulate sympathetic solar flares, revealing that weak magnetic connectivity between active regions best matches observed flare timing distributions.

Contribution

The study develops a two-lattice avalanche model with adjustable connectivity, providing new insights into how magnetic interactions influence sympathetic flaring on the Sun.

Findings

Strong connectivity causes synchronization and excess short waiting time avalanches.

Weak connectivity reproduces observed solar flare waiting time distributions.

Model suggests magnetic connectivity must be weak for realistic sympathetic flare behavior.

Abstract

Avalanche models running in a self-organized critical regime have proven powerful in reproducing the power-law distributions and scale invariance that characterize the statistical properties of solar flares. They are often interpreted as representing an individual active region of the Sun. As a result, this class of models has rarely been applied to describe sympathetic flares $\unicode{x2014}$ solar eruptions that occur in close spatial and temporal proximity, seemingly driven by their mutual interaction. In this study, we investigate the phenomenon of sympathetic flaring using avalanche models and compare their statistical properties with observations of sympathetic flares on the Sun. We developed a novel avalanche model featuring two connected lattices, each representing a distinct active region. This connectivity allows the transfer of nodal variable between the lattices, simulating the non-local effects expected to occur during sympathetic flares. Our results show that under strong connectivity, the lattices exhibit temporal synchronization, with correlations between their avalanche energies. Furthermore, increasing the connectivity between the lattices results in an excess of avalanches at short waiting times. A quantitative comparison with observational data suggests that only a weak connectivity allows our model to replicate the observed solar waiting time distributions. Consequently, we propose that if magnetic connectivity between distinct active regions drives sympathetic flaring on the Sun, it must remain relatively weak.