Magnetic Field Structures Triggering Solar Flares and Coronal Mass Ejections

TL;DR

This study identifies specific small magnetic structures near the magnetic polarity inversion line as key triggers for solar eruptions, enhancing the understanding and potential prediction of solar flares and CMEs through simulations and satellite data analysis.

Contribution

The paper systematically investigates magnetic structures triggering solar eruptions using 3D magnetohydrodynamic simulations and observational data, revealing two key magnetic configurations near the PIL.

Findings

Two types of small magnetic structures favor eruption onset.

Simulations match observed flare events, validating the models.

Forecasting is feasible with detailed magnetic field observations.

Abstract

Solar flares and coronal mass ejections (CMEs), the most catastrophic eruptions in our solar system, have been known to affect terrestrial environments and infrastructure. However, because their triggering mechanism is still not sufficiently understood, our capacity to predict the occurrence of solar eruptions and to forecast space weather is substantially hindered. Even though various models have been proposed to determine the onset of solar eruptions, the types of magnetic structures capable of triggering these eruptions are still unclear. In this study, we solved this problem by systematically surveying the nonlinear dynamics caused by a wide variety of magnetic structures in terms of three-dimensional magnetohydrodynamic simulations. As a result, we determined that two different types of small magnetic structures favor the onset of solar eruptions. These structures, which should appear near the magnetic polarity inversion line (PIL), include magnetic fluxes reversed to the potential component or the nonpotential component of major field on the PIL. In addition, we analyzed two large flares, the X-class flare on December 13, 2006 and the M-class flare on February 13, 2011, using imaging data provided by the Hinode satellite, and we demonstrated that they conform to the simulation predictions. These results suggest that forecasting of solar eruptions is possible with sophisticated observation of a solar magnetic field, although the lead time must be limited by the time scale of changes in the small magnetic structures.