Effective stochastic resonance of coupled excitable elements under noise of unequal amplitude

Effective stochastic resonance (SR) is numerically studied using a model of two coupled excitable FitzHugh-Nagumo elements exposed to noise of unequal amplitude. Compared to previous SR models of a single excitable element and of two coupled excitable elements exposed to noise of equal amplitude, the present model exhibits a more intense resonance to the external signal. To extract the key dynamics of this effective SR, the idea of triggered excitation is introduced. Triggered excitation means a process in which the noise-free element is excited synchronously to the external signal with the triggering action of another element that randomly fluctuates asynchronously to the external signal. A deterministic simulation simply proving the triggered excitation process supports our idea.