title: Transition from spiral waves to defect-mediated turbulence induced by gradient effects in a reaction-diffusion system.
abstract: The transition from spiral waves to defect-mediated turbulence was studied in a spatial open reactor using Belousov-Zhabotinsky reaction. The experimental results show a new mechanism of the transition from spirals to spatiotemporal chaos, in which the gradient effects in the three-dimensional system are essential. The transition scenario consists of two stages: first, the effects of gradients in the third dimension cause a splitting of the spiral tip and a deletion of certain wave segments, generating new wave sources; second, the waves sent by the new wave sources undergo a backfire instability, and the back waves are laterally unstable. As a result, defects are automatically generated and fill all over the system. The result of numerical simulation using the FitzHugh-Nagumo model essentially agrees with the experimental observation.
authors.affiliation: Department of Physics, Peking University, Beijing 100871, China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Ouyang
authors.forename: Bambi
authors.initials: B
authors.lastname: Hu
authors.forename: Gemunu H
authors.initials: GH
authors.lastname: Gunaratne