Transitions to Line-Defect Turbulence in Complex Oscillatory Media

Abstract

The transition from complex-periodic to chaotic behavior is investigated in oscillatory media supporting spiral waves. We find turbulent regimes characterized by the spontaneous nucleation, proliferation, and erratic motion of synchronization defect lines which separate domains of different oscillation phases. The line-defect dynamics is controlled by the competition between diffusion, which reduces line length and curvature, and phase-gradient-induced growth. The onset of each type of defect-line turbulence is identified with a nonequilibrium phase transition characterized by nontrivial critical exponents.