Dynamics of a stochastic oscillator in an excitable chemical reaction system

Dynamics of an excitable Belousov-Zabotinsky reaction system subject to a subthreshold periodic signal and additive noise is investigated using cation exchange beads loaded with the cationic catalyst. We find two kinds of resonance phenomena with respect to the noise amplitude. At the first resonance, the regular oscillation appears with the period equal to the signal period, which is identified as a conventional stochastic resonance. The second resonance is a great contrast to conventional stochastic resonance, in which the regular oscillation appears in a characteristic fashion like phase locking of deterministic oscillators, depending on the signal period and a noise amplitude. Results are explained in terms of the interplay of periodic forcing and the noise-induced oscillator with the period determined by an intrinsic time scale of the system.