Data-Constrained Magnetohydrodynamics Simulation of a Confined X-class Flare in NOAA Active Region 11166

TL;DR

This study uses a data-constrained magnetohydrodynamics simulation to analyze the magnetic structures and reconnection processes responsible for a confined X-class solar flare in NOAA active region 11166, revealing the role of 3D nulls and QSLs.

Contribution

It introduces a novel simulation approach that incorporates non-force-free magnetic extrapolation to accurately model the magnetic topology of a confined flare.

Findings

Reconnection at 3D nulls and QSLs drives pre-flare activity.

The flare is confined due to the anchored spine of the 3D null and lack of flux rope.

Reconnection at open spine nulls may trigger jets away from the flare site.

Abstract

In this paper, we present a magnetohydrodynamics simulation of NOAA active region 11166 to understand the origin of a confined X-class flare that peaked at 23:23 UT on 2011 March 9. The simulation is initiated with a magnetic field extrapolated from the corresponding photospheric magnetogram using a non-force-free-field extrapolation technique. Importantly, the initial magnetic configuration identifies three-dimensional (3D) magnetic nulls and quasi-separatrix layers (QSLs), which nearly agree with the bright structures appeared in multi-wavelength observations. The Lorentz force associated with the extrapolated field self-consistently generates the dynamics that leads to the magnetic reconnections at the 3D nulls and the QSLs. These reconnections are found to contribute to the pre-flare activities and, ultimately, lead to the development of the flare ribbons. Notably, the anchored spine of the 3D null and the complete absence of flux rope in the flaring region are congruent with the confined nature of the flare. Furthermore, the simulation also suggests the role of reconnections at the 3D null with an open spine in the onset of a jet away from the flaring site.