title: Dynamics of a penta-hepta defect in a hexagonal pattern
abstract: The structure and dynamics of a penta-hepta defect in a hexagonal pattern are studied experimentally. The hexagonal pattern is formed by placing a layer of soap bubbles (diameter approximately 1 mm) on a flat glass plate. We find that an isolated penta-hepta defect in a bubble raft with free boundary always moves along the direction perpendicular to the wave vector of the nonsingular mode and towards the nearest boundary. The structure of the penta-hepta defect is found to be similar to that found in nonequilibrium pattern forming systems.
authors.affiliation: Department of Physics, Occidental College, Los Angeles, California 90041, USA.
authors.initials: T
authors.lastname: Tam
authors.initials: D
authors.lastname: Ohata
authors.initials: M
authors.lastname: Wu