Modeling Repeatedly Flaring $\delta$ Sunspots

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.

Minor changes consistent with Phys Rev Lett version

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Cited by in corpus (10)

• Flare-productive active regions
• Magnetic Properties of Solar Active Regions that Govern Large Solar Flares and Eruptions
• Numerical Simulations of Flare-productive Active Regions: delta-sunspots, Sheared Polarity Inversion Lines, Energy Storage, and Predictions
• Different contributions to space weather and space climate from different big solar active regions
• Applying the weighted horizontal magnetic gradient method to a simulated flaring Active Region
• Formation of super-strong horizontal magnetic field in delta-type sunspot in radiation magnetohydrodynamic simulations
• Photospheric Lorentz force changes in eruptive and confined solar flares
• Challenges and Advances in Modeling of the Solar Atmosphere: A White Paper of Findings and Recommendations
• Evolution of reconnection flux during eruption of magnetic flux ropes
• VIEWPOINT: A New Twist in Simulating Solar Flares