Dynamics of Penta-Hepta Defect in a Hexagonal Pattern

Abstract

The spatial and temporal dynamics of penta-hepta defects (PHD) and line defects in hexagonal patterns are studied. The hexagonal pattern is formed by a layer of soap bubbles (~1 mm in diameter) floating on a glass plate. We have found that the defect consistently moves in the direction perpendicular to the wavevector of nonsingular mode [1]. Our findings differ with the theoretical prediction for a different system with the same pattern by 90 degrees. Experimental apparatus includes: CCD camera, video image grabbing computer, and SVHS recorder. 1. Lev Tsimring, Phys. Rev. Lett., 74, 4201 (1995)