Distinguishing between flaring and nonflaring active regions

Soumitra Hazra,Gopal Sardar,Partha Chowdhury

doi:10.1051/0004-6361/201937426

Abstract

Context.Large-scale solar eruptions significantly affect space weather and damage space-based human infrastructures. It is necessary to predict large-scale solar eruptions; it will enable us to protect the vulnerable infrastructures of our modern society.Aims.We investigate the difference between flaring and nonflaring active regions. We also investigate whether it is possible to forecast a solar flare.Methods.We used photospheric vector magnetogram data from the Solar Dynamic Observatory’s Helioseismic Magnetic Imager to study the time evolution of photospheric magnetic parameters on the solar surface. We built a database of flaring and nonflaring active regions observed on the solar surface from 2010 to 2017. We trained a machine-learning algorithm with the time evolution of these active region parameters. Finally, we estimated the performance obtained from the machine-learning algorithm.Results.The strength of some magnetic parameters such as the total unsigned magnetic flux, the total unsigned magnetic helicity, the total unsigned vertical current, and the total photospheric magnetic energy density in flaring active regions are much higher than those of the non-flaring regions. These magnetic parameters in a flaring active region evolve fast and are complex. We are able to obtain a good forecasting capability with a relatively high value of true skill statistic. We also find that time evolution of the total unsigned magnetic helicity and the total unsigned magnetic flux provides a very high ability of distinguishing flaring and nonflaring active regions.Conclusions.We can distinguish a flaring active region from a nonflaring region with good accuracy. We confirm that there is no single common parameter that can distinguish all flaring active regions from the nonflaring regions. However, the time evolution of the top two magnetic parameters, the total unsigned magnetic flux and the total unsigned magnetic helicity, have a very high distinguishing capability.

Highlights

Solar flares and coronal mass ejections are the two greatest explosions in the Solar System
These results indicate that the time evolution of the total unsigned magnetic helicity and the total unsigned magnetic flux is the best indicator in terms of distinguishing capability
We selected two eruptive active regions and one noneruptive active region to determine the difference between the time evolution of the magnetic complexity in eruptive and noneruptive active regions

Summary

Introduction

Solar flares and coronal mass ejections are the two greatest explosions in the Solar System These two explosions release a huge amount of magnetic energy into the solar corona, creating disturbances in space weather. These two events directly affect the Earth’s atmosphere, causing geomagnetic disturbances. The study of magnetic fields in the Sun is critical for understanding the energy buildup and release mechanism in solar flares and coronal mass ejection. Solar flares and coronal mass ejections are believed to be a storage-and-release mechanism by which the nonpotential magnetic field of the solar corona is released abruptly (Priest & Forbes 2002; Shibata & Magara 2011). Individual case studies indicate a strong relationship between these nonpotentiality parameters and the flare productivity, it is unclear so far which property is common in all the eruptive active regions and distinguishes them from other noneruptive active regions

Objectives

Results

Conclusion