Interactions and dynamics of topological defects: Theory and experiments near the onset of weak turbulence

Abstract

The dynamics of a single topological defect and the interaction between pairs, including the process of annihilation of defects of opposite topological charge, are studied experimentally and theoretically near the onset of weak turbulence in Williams domains of electroconvecting nematics. The existence of topological defects requires a gauge field theoretical treatment, enriching the commonly used ‘‘amplitude equations.’’ The gauge field carries the interaction which is found to be of finite range in agreement with detailed observations.