Convectively driven vortex flows in the Sun

TL;DR

This paper reports the discovery of small vortex flows in the Sun, created by convective downdrafts, detected via magnetic bright points, with properties linked to solar surface structures, confirming theoretical predictions.

Contribution

First observational evidence of small convectively driven vortex flows in the Sun, matching theoretical predictions and revealing their distribution and dynamics.

Findings

Vortexes occur at a rate of 0.009 per Mm^2

Average lifetime of vortexes is about 5 minutes

Vortexes are associated with magnetic bright points and supergranulation patterns

Abstract

We have discovered small whirlpools in the Sun, with a size similar to the terrestrial hurricanes (<~0.5 Mm). The theory of solar convection predicts them, but they had remained elusive so far. The vortex flows are created at the downdrafts where the plasma returns to the solar interior after cooling down, and we detect them because some magnetic bright points (BPs) follow a logarithmic spiral in their way to be engulfed by a downdraft. Our disk center observations show 0.009 vortexes per Mm^2, with a lifetime of the order of 5 min, and with no preferred sense of rotation. They are not evenly spread out over the surface, but they seem to trace the supergranulation and the mesogranulation. These observed properties are strongly biased by our type of measurement, unable to detect vortexes except when they are engulfing magnetic BPs.