Solar Vortex Tubes: Vortex Dynamics in the Solar Atmosphere

TL;DR

This study applies a vortex detection method to numerical simulations of the solar atmosphere, revealing the structure, dynamics, and magnetic interactions of solar vortex tubes from the photosphere to the chromosphere.

Contribution

It introduces a novel application of the Instantaneous Vorticity Deviation method to solar magnetoconvection simulations, providing detailed insights into vortex morphology and magnetic interactions.

Findings

Vortex tubes are distributed along intergranular regions with coned shapes.

Magnetic fields influence vortex dynamics and vorticity evolution.

Eddy viscosity effects slow plasma motion towards vortex centers.

Abstract

In this work, a state-of-the-art vortex detection method, Instantaneous Vorticity Deviation, is applied to locate three-dimensional vortex tube boundaries in numerical simulations of solar photospheric magnetoconvection performed by the MURaM code. We detected three-dimensional vortices distributed along intergranular regions and displaying coned shapes that extend from the photosphere to the low chromosphere. Based on a well-defined vortex center and boundary, we were able to determine averaged radial profiles and thereby investigate the dynamics across the vortical flows at different height levels. The solar vortex tubes present nonuniform angular rotational velocity, and, at all height levels, there are eddy viscosity effects within the vortices, which slow down the plasma as it moves toward the center. The vortices impact the magnetic field as they help to intensify the magnetic field at the sinking points, and in turn, the magnetic field ends up playing an essential role in the vortex dynamics. The magnetic field was found to be especially important to the vorticity evolution. On the other hand, it is shown that, in general, kinematic vortices do not give rise to magnetic vortices unless their tangential velocities at different height levels are high enough to overcome the magnetic tension.