Vortex Tubes of Turbulent Solar Convection

TL;DR

This paper investigates how vortex tubes form in turbulent solar convection using high-resolution simulations, revealing two main mechanisms: convective instability and shear flow instability, which generate small-scale vorticity.

Contribution

It identifies and analyzes the primary processes responsible for vortex tube formation in solar surface convection through realistic radiative hydrodynamic simulations.

Findings

Vortex tubes form via convective instability within granules.

Kelvin-Helmholtz instability occurs in intergranular lanes.

Vortex stretching is a key mechanism for small-scale vorticity generation.

Abstract

Investigation of the turbulent properties of solar convection is extremely important for understanding the multi-scale dynamics observed on the solar surface. In particular, recent high-resolution observations have revealed ubiquitous vortical structures, and numerical simulations have demonstrated links between vortex tube dynamics and magnetic field organization and have shown the importance of vortex tube interactions in the mechanisms of acoustic wave excitation on the Sun. In this paper we investigate the mechanisms of the formation of vortex tubes in highly-turbulent convective flows near the solar surface by using realistic radiative hydrodynamic LES simulations. Analysis of data from the simulations indicates two basic processes of vortex tube formation: 1) development of small-scale convective instability inside convective granules, and 2) a Kelvin-Helmholtz type instability of shearing flows in intergranular lanes. Our analysis shows that vortex stretching during these processes is a primary source of generation of small-scale vorticity on the Sun.