Controllable switching between stable modes in a small network of pulse-coupled chemical oscillators

Switching between stable oscillatory modes in a network of four Belousov-Zhabotinsky oscillators coupled in a ring via unidirectional inhibitory pulsatile coupling with a time delay is analysed computationally and experimentally. There are five stable modes in this network: in-phase, anti-phase, walk, walk reverse, and three-cluster modes. Transitions between the modes are carried out by short external pulses applied to one or several oscillators. We consider three types of switching between the modes: (i) forced switching, when the phases of oscillators of an initial mode reset in such a way that they correspond to the phases of the final mode; internal pulses of the network play no role in this resetting; (ii) "specific" switching, when the phase of only one oscillator is changed by an external perturbation which induces a chain of phase changes in other oscillators due to internal coupling between oscillators; and (iii) multistep switching through intermediate modes, which can be either stable or unstable attractors. All these types of switching have been found in simulations and verified in laboratory experiments.