MHD Simulation of a Sigmoid Eruption of Active Region 11283

TL;DR

This paper demonstrates a realistic MHD simulation of a solar sigmoid eruption using a nonlinear force-free field extrapolation, closely matching observations and revealing the eruption's initiation mechanism involving null points and torus instability.

Contribution

It introduces a method to simulate solar eruptions with realistic initial magnetic fields reconstructed from observations, advancing understanding of eruption triggers.

Findings

Reconstructed the pre-eruption magnetic field from observations.

Simulated eruption closely matches SDO/AIA observations.

Identified null point and torus instability as key eruption triggers.

Abstract

Current magnetohydrodynamic (MHD) simulations of the initiation of solar eruptions are still commonly carried out with idealized magnetic field models, whereas the realistic coronal field prior to eruptions can possibly be reconstructed from the observable photospheric field. Using a nonlinear force-free field extrapolation prior to a sigmoid eruption in AR 11283 as the initial condition in a MHD model, we successfully simulate the realistic initiation process of the eruption event, as is confirmed by a remarkable resemblance to the SDO/AIA observations. Analysis of the pre-eruption field reveals that the envelope flux of the sigmoidal core contains a coronal null and furthermore the flux rope is prone to a torus instability. Observations suggest that reconnection at the null cuts overlying tethers and likely triggers the torus instability of the flux rope, which results in the eruption. This kind of simulation demonstrates the capability of modeling the realistic solar eruptions to provide the initiation process.