Chiral Pattern in Nonrotating Spherical Convection

TL;DR

This paper reports the discovery of a novel steady convection pattern in nonrotating spherical shells, characterized by tetrahedral symmetry and spiral roll arrangements, differing from previously known symmetric solutions.

Contribution

The study reveals a new convection pattern with tetrahedral symmetry and no reflection symmetry, identified through computer simulations in nonrotating spherical shells.

Findings

Discovered a new steady convection pattern with tetrahedral symmetry.

Pattern consists of six pairs of spiral rolls on 12 faces.

Two mirror-image configurations depending on spiral winding.

Abstract

When the Rayleigh number is low, Rayleigh-B\'enard convection in a nonrotating spherical shell with central gravity has symmetric solutions in terms of three-dimensional discrete rotation. All the known patterns with the regular polyhedral symmetries accompany reflection symmetry. We found a new type of steady convection in a nonrotating spherical shell by computer simulations. The pattern has the discrete rotational symmetry of a regular tetrahedron with no reflection symmetry. The convection consists of six pairs of spiral rolls placed on 12 faces of a spherical dodecahedron. Depending on the winding of the spirals, there are two possible configurations that are mirror images of one another.