Excitable Structures in Stochastic Bistable Media

We examine the influence of parametric noise on the spatiotemporal behavior of a bistable medium with activator–inhibitor dynamics. Deterministic front propagation in one dimension is seen to be destabilized by the external noise, resulting in the propagation of solitary pulses through the system. For large enough noise levels, this state becomes unstable via a backfiring mechanism, which eventually leads to a turbulent state.