Flare Energy Release in the Lower Solar Atmosphere Near the Magnetic Field Polarity Inversion Line

TL;DR

This study investigates the mechanisms of flare energy release in the lower solar atmosphere near the magnetic polarity inversion line, combining high-resolution observations and magnetic field modeling to identify magnetic reconnection processes.

Contribution

It provides detailed observational and modeling evidence of magnetic flux rope interactions and reconnection near the PIL during an M1-class solar flare.

Findings

Magnetic flux ropes interact and form a current sheet along the PIL.

Energy release occurs in the chromosphere near the PIL.

Magnetic reconnection is triggered by flux rope interaction.

Abstract

We study flare processes in the solar atmosphere using observational data for a M1-class flare of June 12, 2014, obtained by New Solar Telescope (NST/BBSO) and Helioseismic Magnetic Imager (HMI/SDO). The main goal is to understand triggers and manifestations of the flare energy release in the photosphere and chromosphere using high-resolution optical observations and magnetic field measurements. We analyze optical images, HMI Dopplergrams and vector magnetograms, and use Non-Linear Force-Free Field (NLFFF) extrapolations for reconstruction of the magnetic topology and electric currents. The NLFFF modelling reveals interaction of two magnetic flux ropes with oppositely directed magnetic field in the PIL. These flux ropes are observed as a compact sheared arcade along the PIL in the high-resolution broad-band continuum images from NST. In the vicinity of PIL, the NST H alpha observations reveal formation of a thin three-ribbon structure corresponding to a small-scale photospheric magnetic arcade. The observational results evidence in favor of location of the primary energy release site in the chromospheric plasma with strong electric currents concentrated near the polarity inversion line. In this case, magnetic reconnection is triggered by the interacting magnetic flux ropes forming a current sheet elongated along the PIL.