Evolution of twist-shear and dip-shear in Faring active region NOAA 10930

TL;DR

This study investigates how magnetic shear angles, specifically twist-shear and dip-shear, evolve in a flare-active region NOAA 10930, revealing contrasting post-flare behaviors of these shear components.

Contribution

It introduces a detailed analysis of both horizontal and vertical magnetic shear angles and their evolution during a solar flare in NOAA 10930.

Findings

Twist-shear increases after the flare.

Dip-shear decreases significantly after the flare.

Shear angles vary distinctly in response to flare activity.

Abstract

We study the evolution of magnetic shear angle in a flare productive active region NOAA 10930. The magnetic shear angle is defined as the deviation in the orientation of the observed magnetic field vector with respect to the potential field vector. The shear angle is measured in horizontal as well as vertical plane. The former is computed by taking the difference between the azimuth angles of the observed and potential field and is called the twist-shear, while the latter is computed by taking the difference between the inclination angles of the observed and potential field and is called the dip-shear. The evolution of the two shear angles is then tracked over a small region located over the sheared penumbra of the delta sunspot in NOAA 10930. We find that, while the twist-shear shows an increasing trend after the flare the dip-shear shows a significant drop after the flare.