Experimental observation of internal signal stochastic resonance in the Belousov-Zhabotinsky reaction

We show experimentally the phenomenon of internal signal stochastic resonan ce in the Belousov-Zhabotinsky reaction without external signal. The chemic al reaction is placed in an excitable state near a Hopf bifurcation in a CS TR. When the flow rate is perturbed by stochastic noise, noise-induced osci llations are observed, and two closely spaced, large-amplitude spikes appea r nearly periodically at the proper noise level. More importantly, analysis from the power spectra and interspike interval histogram of the time serie s output, the coherence of these noise-induced oscillations, is maximal at an optimal noise intensity, indicating the occurrence of internal signal st ochastic resonance.