STOCHASTIC RESONANCE IN ON-OFF INTERMITTENCY

Stochastic resonance (SR) is studied in chaotic systems exhibiting on- off intermittency (OOI). They include a discrete-time system-the logis tic map with the control parameter varying randomly in time and a cont inuous-time system-chaotic oscillators just below the synchroniation t hreshold. As a weak additive or multiplicative periodic forcing is add ed to such systems, the signal-to-noise ratio (SNR) exhibits a maximum as a function of the intermittency control parameter. In all cases SN R shows dependence on the forcing frequency. In the case of additive p eriodic forcing in continuous-time systems a distinct minimum of SNR i s observed when the periodic forcing frequency is close to the charact eristic frequency of chaotic oscillations of the system. Tn the case o f multiplicative periodic forcing this dependence retains even for ver y small frequencies; this is a result of a very long characteristic ti me scale, typical of systems with OOI.