On the prevalence of small-scale twist in the solar chromosphere and transition region

TL;DR

This study uses high-resolution IRIS and SST observations to investigate small-scale twist motions in the solar chromosphere and transition region, revealing their potential role in heating the solar atmosphere.

Contribution

It provides new high-resolution observational evidence of ubiquitous small-scale twist motions in the solar chromosphere and TR, linking these motions to rapid heating processes.

Findings

Ubiquitous twist motions observed across various solar regions.

Twisting motions are associated with rapid heating to TR temperatures.

High-resolution data reveal small-scale torsional dynamics in the solar atmosphere.

Abstract

The solar chromosphere and transition region (TR) form an interface between the Sun's surface and its hot outer atmosphere. Here most of the non-thermal energy that powers the solar atmosphere is transformed into heat, although the detailed mechanism remains elusive. High-resolution (0.33-arcsec) observations with NASA's Interface Region Imaging Spectrograph (IRIS) reveal a chromosphere and TR that are replete with twist or torsional motions on sub-arcsecond scales, occurring in active regions, quiet Sun regions, and coronal holes alike. We coordinated observations with the Swedish 1-m Solar Telescope (SST) to quantify these twisting motions and their association with rapid heating to at least TR temperatures. This view of the interface region provides insight into what heats the low solar atmosphere.