Magnetic Field Restructuring Associated with Two Successive Solar Eruptions

TL;DR

This study analyzes two major solar eruptions, revealing significant magnetic energy release, helicity changes, and the role of the 'implosion' phenomenon in flare dynamics using advanced magnetic field extrapolation techniques.

Contribution

It provides detailed magnetic field reconfiguration analysis of successive solar eruptions, highlighting the relationship between magnetic energy, helicity, and the 'implosion' phenomenon.

Findings

20%-30% decrease in magnetic free energy during eruptions

Sign changes in helicity injection rate linked to eruptions

'Implosion' phenomenon associated with the first X-class flare

Abstract

We examine two successive flare eruptions (X5.4 and X1.3) on 2012 March 7 in the NOAA active region 11429 and investigate the magnetic field reconfiguration associated with the two eruptions. Using an advanced non-linear force-free field (NLFFF) extrapolation method based on the SDO/HMI vector magnetograms, we obtain a stepwise decrease in the magnetic free energy during the eruptions, which is roughly 20%-30% of the energy of the pre-flare phase. We also calculate the magnetic helicity, and suggest that the changes of the sign of the helicity injection rate might be associated with the eruptions. Through the investigation of the magnetic field evolution, we find that the appearance of the "implosion" phenomenon has a strong relationship with the occurrence of the first X-class flare. Meanwhile, the magnetic field changes of the successive eruptions with implosion and without implosion were well observed.