Modeling Repeatedly Flaring $\delta$ Sunspots

TL;DR

This paper presents a simulation of the Sun's active regions that reproduces the formation of delta sunspots and their associated phenomena, including repeated flares and coronal mass ejections, from primitive initial conditions.

Contribution

It introduces a novel simulation approach starting from a magnetic sheet, successfully modeling the formation and activity of delta sunspots and related solar phenomena.

Findings

Simulation reproduces delta sunspot formation from primitive magnetic structures.

Repeated flaring and flux rope ejections observed in the simulation.

Results resemble observed solar active region behaviors.

Abstract

Active regions (AR) appearing on the surface of the Sun are classified into $\alpha$, $\beta$, $\gamma$, and $\delta$ by the rules of the Mount Wilson Observatory, California on the basis of their topological complexity. Amongst these, the $\delta$-sunspots are known to be super-active and produce the most X-ray flares. Here, we present results from a simulation of the Sun by mimicking the upper layers and the corona, but starting at a more primitive stage than any earlier treatment. We find that this initial state consisting of only a thin sub-photospheric magnetic sheet breaks into multiple flux-tubes which evolve into a colliding-merging system of spots of opposite polarity upon surface emergence, similar to those often seen on the Sun. The simulation goes on to produce many exotic $\delta$-sunspot associated phenomena: repeated flaring in the range of typical solar flare energy release and ejective helical flux ropes with embedded cool-dense plasma filaments resembling solar coronal mass ejections.