Coupling from the photosphere to the chromosphere and the corona

TL;DR

This paper reviews the complex multi-scale physical processes and magnetic coupling in the Sun's atmosphere, emphasizing recent observational and simulation insights into the quiet Sun's dynamic and intermittent nature.

Contribution

It provides a comprehensive synthesis of recent observational and numerical simulation results on the multi-scale coupling in the Sun's atmosphere, highlighting the role of magnetic fields and shock waves.

Findings

Magnetic fields couple the photosphere, chromosphere, and corona across multiple scales.

The quiet Sun's atmosphere is highly dynamic and intermittent.

Shock waves significantly influence the internetwork regions.

Abstract

The atmosphere of the Sun is characterized by a complex interplay of competing physical processes: convection, radiation, conduction, and magnetic fields. The most obvious imprint of the solar convection and its overshooting in the low atmosphere is the granulation pattern. Beside this dominating scale there is a more or less smooth distribution of spatial scales, both towards smaller and larger scales, making the Sun essentially a multi-scale object. Convection and overshooting give the photosphere its face but also act as drivers for the layers above, namely the chromosphere and corona. The magnetic field configuration effectively couples the atmospheric layers on a multitude of spatial scales, for instance in the form of loops that are anchored in the convection zone and continue through the atmosphere up into the chromosphere and corona. The magnetic field is also an important structuring agent for the small, granulation-size scales, although (hydrodynamic) shock waves also play an important role -- especially in the internetwork atmosphere where mostly weak fields prevail. Based on recent results from observations and numerical simulations, we attempt to present a comprehensive picture of the atmosphere of the quiet Sun as a highly intermittent and dynamic system.