Small-scale structure and dynamics of the chromospheric magnetic field

TL;DR

Recent high-resolution observations and simulations have transformed our understanding of the solar chromosphere from a static layer to a dynamic, complex structure with small-scale magnetic and shock features.

Contribution

This paper provides new observational constraints on the small-scale structure and dynamics of the quiet Sun chromosphere using high-resolution data from the Swedish Solar Telescope.

Findings

Identification of fibrillar magnetic structures in the chromosphere

Detection of propagating shock waves in internetwork regions

Evidence of interaction between weak magnetic fields and large-scale fields

Abstract

Recent advances in observational performance and numerical simulations have revolutionised our understanding of the solar chromosphere. This concerns in particular the structure and dynamics on small spatial and temporal scales. As a result, the picture of the solar chromosphere changed from an idealised static and plane-parallel stratification to a complex compound of intermittent domains, which are dynamically coupled to the layers below and above. In this picture, the chromosphere in a stricter sense is associated with the typical fibrillar structure shaped by magnetic fields like it is known from images taken in the H alpha line core. In internetwork regions below this layer, there exists a domain with propagating shock waves and weak magnetic fields, which both probably interact with the overlying large scale field. The existence of such a sub-canopy domain certainly depends on the properties of the overlying field. Details of the structure of the lower atmosphere can therefore be expected to vary significantly from location to location. Here, high-resolution observations, which were obtained with the CRISP filter at the Swedish Solar Telescope, are used to derive qualitative constraints for the atmospheric structure of quiet Sun regions.