A Contemporary View of Coronal Heating

TL;DR

This paper reviews the ongoing challenge of identifying the dominant mechanisms responsible for heating the Sun's corona, emphasizing the complex, coupled nature of the solar atmosphere and recent progress in understanding potential contributors.

Contribution

It provides a comprehensive overview of current theories and factors influencing the coronal heating problem, highlighting recent advancements and remaining uncertainties.

Findings

Magnetic fields are crucial in coronal heating.

Multiple mechanisms likely contribute to heating.

Recent observational and computational progress has advanced understanding.

Abstract

Determining the heating mechanism (or mechanisms) that causes the outer atmosphere of the Sun, and many other stars, to reach temperatures orders of magnitude higher than their surface temperatures has long been a key problem. For decades the problem has been known as the coronal heating problem, but it is now clear that `coronal heating' cannot be treated or explained in isolation and that the heating of the whole solar atmosphere must be studied as a highly coupled system. The magnetic field of the star is known to play a key role, but, despite significant advancements in solar telescopes, computing power and much greater understanding of theoretical mechanisms, the question of which mechanism or mechanisms are the dominant supplier of energy to the chromosphere and corona is still open. Following substantial recent progress, we consider the most likely contenders and discuss the key factors that have made, and still make, determining the actual (coronal) heating mechanism (or mechanisms) so difficult.