External localized harmonic influence on an incoherence cluster of chimera states

Abstract We study impacts of external harmonic forces on chimera states in an ensemble of chaotic Rossler oscillators with nonlocal interaction. The main attention is paid to control the spatial structure by applying a targeted localized excitation on an incoherence cluster. This influence on a phase chimera enables us to eliminate the incoherence cluster and to realize the regime with a piecewise smooth spatial profile. The mechanism of elimination of the incoherence cluster of the phase chimera consists in-phase synchronization of all oscillators within the region of influence of the external force. This phenomenon is observed for a sufficiently wide range of the external force frequency, especially when its value is less than the natural frequency. Increasing the external force amplitude can lead to two scenarios depending on the dynamics of individual oscillators. In the case of regular dynamics, a strong force induces another type of the incoherence cluster within the region of the external force influence. The oscillator dynamics within this region becomes chaotic. Thus, the features of this cluster are similar to those for the incoherence cluster of an amplitude chimera. When the dynamics is chaotic, the force can cause the system to switch to the regime of a metastable spatial distribution with a qualitatively different character at different time intervals. It is impossible to eliminate the incoherence cluster of the amplitude chimera by means of the localized harmonic influence for any values of its parameters. The destruction of the amplitude chimera structure under the influence of the external force leads either to the intermittent regime or to inducing the stable incoherence cluster.