NOISE-INDUCED PATTERN TRANSITION AND SPATIOTEMPORAL STOCHASTIC RESONANCE

The influence of parametric noise on the spatiotemporal dynamics of a two-variable reaction-diffusion model, describing pattern formation in excitable media, is investigated. When a control parameter is perturb ed by stochastic force with suitable intensity, noise induced pattern transition between ''single'' spiral wave and ''double'' spiral waves, which does not occur in the absence of noise, is observed. If this pa rameter also varies periodically in time around the bifurcation point, we find that the output signal-to-noise ratios show maxima with the v ariation of noise intensity, indicating the occurrence of spatiotempor al stochastic resonance.