The core structure of a laboratory-made dust devil-like vortex and its condensed matter analogs

Abstract

We consider the defect core structures of topological line defects characterized by a winding number k=1. In the experimental part of the work, we illustrate a simple and robust method of creating a laboratory-scale air-flow vortex, simulating a dust devil. We stabilized an escaped-type non-singular vortex-type configuration in the small-scale confined convective system with a converging inflow with imposed shear but lack of horizontal vorticity. Furthermore, we show that analogous defect core structures could be stabilized in simple condensed matter systems. In particular, different liquid crystalline phases represent an ideal testing ground to study different topological defects due to their unique combination of fluidity, softness, optical anisotropy, and rich diversity of defect configurations. In the theoretical and numerical study, we focused on the most common static k=1 line defect core structures in vector and nematic ordering. Namely, these two cases exhibit two different symmetries and can consequently exhibit qualitatively different defect core structures. We discuss conditions stabilizing either singular or non-singular core structures.