Evolution of Photospheric Flow and Magnetic Fields Associated with The 2015 June 22 M6.5 Flare

Abstract

The evolution of photospheric flow and magnetic fields before and after flares can provide important information regarding the flare triggering and back reaction processes. However, such studies on the flow field are rare due to the paucity of high-resolution observations covering the entire flaring period. Here we study the structural evolution of penumbra and shear flows associated with the 2015 June 22 M6.5 flare in NOAA AR 12371, using high-resolution imaging observation in the TiO band taken by the 1.6~m Goode Solar Telescope at Big Bear Solar Observatory, with the aid of the differential affine velocity estimator method for flow tracking. The accompanied photospheric vector magnetic field changes are also analyzed using data from the Helioseismic and Magnetic Imager. As a result, we found, for a penumbral segment in the negative field adjacent to the magnetic polarity inversion line (PIL), an enhancement of penumbral flows (up to an unusually high value of \sm2~\kms) and extension of penumbral fibrils after the first peak of the flare hard X-ray (HXR) emission. We also found an area at the PIL, which is co-spatial with a precursor brightening kernel, exhibits a gradual increase of shear flow velocity (up to \sm0.9~\kms) after the flare. The enhancing penumbral and shear flow regions are also accompanied by an increase of horizontal field and decrease of magnetic inclination angle(measured from the solar surface). These results are discussed in the context of the theory of back reaction of coronal restructuring on the photosphere as a result of flare energy release.

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Cited by in corpus (10)

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• Identifying and Tracking Solar Magnetic Flux Elements with Deep Learning
• Onset Mechanism of M6.5 Solar Flare Observed in Active Region 12371
• Comparative study of electric currents and energetic particle fluxes in a solar flare and Earth magnetospheric substorm
• Photospheric response to a flare
• Formation and Eruption of Hot Channels during an M6.5 Class Solar Flare
• Multi-instrument Comparative Study of Temperature, Number Density, and Emission Measure during the Precursor Phase of a Solar Flare