# Fine Magnetic Characteristics of a Light Bridge by Hinode

## TL;DR

This study analyzes the magnetic properties of a light bridge in a sunspot using Hinode satellite data, revealing distinct magnetic characteristics that suggest different magnetic systems and potential for magnetic reconnection.

## Contribution

It provides detailed measurements of magnetic parameters in a light bridge, highlighting differences from the umbra and suggesting separate magnetic systems.

## Key findings

- Higher amplitudes of $ ext{α}$ and $J_z$ in LB compared to umbra
- Presence of two sign regions of $J_z$ along LB
- Smaller and sign-changing tension force $T_z$ in LB

## Abstract

Light bridge (LB) is bright structure crossing the umbra of sunspots and associated to the breakup or assembly of sunspots. In this paper, a LB is presented and studied using the observatory data obtained by {\it Hinode} satellites. Force-free factor ($\alpha$) and the z-component of current ($J_{z}$) and tension force ($T_{z}$) are calculated basing on the vector magnetograms observed by Spectro-Polarimeter (SP) of the Solar Optical Telescope (SOT) on board {\it Hinode}. It is found that the amplitudes of $\alpha$ and $J_{z}$ of LB are generally larger than those of umbra. It is found that there are two signs of $J_{z}$ along LB, which are divided at near the middle position of LB. It is found that the amplitudes of $T_{z}$ of LB are smaller than those of umbra and there are changes of sign of $T_{z}$ between the boundary of LB and umbra. Through comparisons and investigations, it suggest that LB and umbra maybe two different magnetic systems, which is a necessary condition for interaction magnetic reconnection.