Innovative and automated method for vortex identification. II. Application to numerical simulations of the solar atmosphere

Abstract

Ubiquitous small-scale vortical motions are seen to occur in the solar atmosphere both in simulations and observations. They are thought to play a significant role in the local heating of the quiet chromosphere and corona. In a previous paper, we proposed a new method for the automated identification of vortices based on the accurate estimation of curvature centers; this method was implemented in the SWIRL algorithm. We aim to assess the applicability of the SWIRL algorithm to self-consistent numerical simulations of the solar atmosphere. The highly turbulent and dynamical solar flow poses a challenge to any vortex-detection method. We also conduct a statistical analysis of the properties and characteristics of photospheric and chromospheric small-scale swirling motions in numerical simulations. h $ of physical time. Mm Mm km $ throughout the simulated atmosphere. We also find an approximately linear correlation between the rotational speed of chromospheric swirls and the local Alfvén speed. We find evidence that more than $80\,<!PCT!>$ of the identified, coherent, vortical structures may be Alfvénic in nature. The SWIRL algorithm is a reliable tool for the identification of vortical motions in magnetized, turbulent, and complex astrophysical flows. It can serve to expand our understanding of the nature and properties of swirls in the solar atmosphere. A statistical analysis shows that swirling structures may be smaller, more numerous, and may rotate faster than previously thought, and also suggests a tight relation between swirls and the propagation of Alfvénic waves in the solar atmosphere.