A Statistical Study on Property of Spatial Magnetic Field for Solar Active Region

TL;DR

This study statistically analyzes the relationship between spatial magnetic fields and solar flares, revealing that magnetic field lines and free energy generally decrease after flares in most active regions.

Contribution

It provides new statistical evidence on how magnetic field properties change post-flare, based on a decade of observations from Huairou Solar Observing Station.

Findings

Magnetic field lines become lower after flares in 69% of cases.

Free magnetic energy decreases after flares in 74% of cases.

Most active regions show magnetic field changes consistent with previous studies.

Abstract

Magnetic fields dominate most solar activities, there exist direct relations between solar flare and the distributions of magnetic field, and also its corresponding magnetic energy. In this paper, the statistical results about the relationships between the spatial magnetic field and solar flare are given basing on vector magnetic field observed by the Solar Magnetic Field Telescope (SMFT) at Huairou Solar Observing Station (HSOS). The spatial magnetic fields are obtained by extrapolated photosphere vector magnetic field observed by SMFT. There are 23 active regions with flare eruption are chosen as data samples, which were observed from 1997 to 2007. The results are as follows: 1. Magnetic field lines become lower after flare for 16(69%) active regions; 2. The free energy are decreased after flare for 17 (74%) active regions. It can conclude that for most active regions the changes of magnetic field after solar flare are coincident with the previous observations and studies.