Structure and Evolution of Magnetic Fields Associated with Solar Eruptions (Invited Review)

TL;DR

This review discusses the evolution of solar magnetic fields in active regions, their role in eruptions, and recent observational advances that enhance understanding of magnetic restructuring during solar flares.

Contribution

It synthesizes recent observational and theoretical developments in understanding magnetic field changes associated with solar eruptions, highlighting new insights from advanced solar observatories.

Findings

Magnetic complexity and flux emergence contribute to energy buildup.

Rapid, irreversible magnetic field changes occur during flares.

Recent observations reveal detailed magnetic restructuring during eruptions.

Abstract

This paper reviews the studies of solar photospheric magnetic field evolution in active regions and its relationship to solar flares. It is divided into two topics, the magnetic structure and evolution leading to solar eruptions and the rapid changes of photospheric magnetic field associated with eruptions. For the first topic, we describe the magnetic complexity, new flux emergence, flux cancellation, shear motions, sunspot rotation, and magnetic helicity injection, which may all contribute to the storage and buildup of energy and triggering of solar eruptions. For the second topic, we concentrate on the observations of rapid and irreversible changes of photospheric magnetic field associated with flares, and the implication on the restructuring of three-dimensional magnetic field. In particular, we emphasize the recent advances in observations of photospheric magnetic field, as state-of-the-art observing facilities (such as Hinode and Solar Dynamic Observatory) become available. The linkage between observations and theories and future prospectives in this research area are also discussed.