Stochastic resonance in the presence or absence of external signal in the continuous stirred tank reactor system

A two variable model, which has been proposed to describe a first-order, ex othermic, irreversible reaction A --> B carried out in a continuous stirred tank reactor (CSTR), is investigated when the control parameter is modulat ed by random and/or periodic forces. Within the bistable region where a lim it cycle and a stable node coexist, stochastic resonance (SR) is observed w hen both random and periodic modulations are present. In the absence of per iodic external signal noise induced coherent oscillations (NICO) appear whe n the control parameter is randomly modulated near the supercritical Hopf b ifurcation point. In addition, the NICO-strength goes through a maximum wit h the increment of the noise intensity, characteristic for the occurrence o f internal signal stochastic resonance (ISSR). (C) 1999 American Institute of Physics. [S0021-9606(99)51525-0].