Photospheric Pore Rotation Associated with a C-class Flare from Spectropolarimetric Observations with DKIST

TL;DR

This study uses high-resolution DKIST spectropolarimetric data to analyze photospheric magnetic field changes and pore rotation associated with a C-class solar flare, revealing magnetic topology and Lorentz force dynamics.

Contribution

It provides new insights into the photospheric magnetic field evolution and pore rotation during a solar flare using advanced high-resolution observations and data-driven magnetic field modeling.

Findings

30% change in horizontal Lorentz force at flare peak

Oppositely-polarity pores exhibited rotational motion

Complex magnetic topology with null-point-like configuration

Abstract

We present high-resolution observations of a C4.1-class solar flare (SOL2023-05-03T20:53) in AR 13293 from the ViSP and VBI instruments at the DKIST. The fast cadence, good resolution, and high polarimetric sensitivity of ViSP data provide a unique opportunity to explore the photospheric magnetic fields before and during the flare. We infer the magnetic field vector in the photosphere from the Fe I 6302 line using Milne-Eddington inversions. Combined analysis of the inverted data and VBI images reveals the presence of two oppositely-polarity pores exhibiting rotational motion both prior to and throughout the flare event. Data-driven simulations further reveal a complex magnetic field topology above the rotating pores, including a null-point-like configuration. We observed a 30% relative change in the horizontal component ($\delta F_h$) of Lorentz force at the flare peak time and roughly no change in the radial component. We find that the changes in $\delta F_h$ are the most likely driver of the observed pore rotation. These findings collectively suggest that the back-reaction of magnetic field line reconfiguration in the corona may influence the magnetic morphology and rotation of pores in the photosphere on a significantly smaller scale.