Stationary and non-stationary chimeras in an ensemble of chaotic self-sustained oscillators with inertial nonlinearity

We study spatial structures arising in an ensemble of Anishchenko–Astakhov chaotic self-sustained oscillators with non-local coupling. Diagrams of the regimes realizing in this system are constructed numerically. The peculiarities of formation of chimera states appearing with decreasing the coupling strength are analyzed. A new type of the chimera state which is born from the traveling wave regime is demonstrated.

     

Influence of a Reactive Power on the Dynamics of an Ensemble of Oscillators Simulated by the Phase Equations with Inertia

Radiophysics and Quantum Electronics - We study the simplest artificial model of a power-network operation. The original model has a ring topology consisting of locally coupled power generators...     

Stability and Noise-induced Transitions in an Ensemble of Nonlocally Coupled Chaotic Maps

The influence of noise on chimera states arising in ensembles of nonlocally coupled chaotic maps is studied. There are two types of chimera structures that can be obtained in such ensembles: phase and amplitude chimera states. In this work, a series of numerical experiments is carried out to uncover the impact of noise on both types of chimeras. The noise influence on a chimera state in the regime of periodic dynamics results in the transition to chaotic dynamics. At the same time, the transformation of incoherence clusters of the phase chimera to incoherence clusters of the amplitude chimera occurs. Moreover, it is established that the noise impact may result in the appearance of a cluster with incoherent behavior in the middle of a coherence cluster.     

Hard and soft excitation of oscillations in memristor-based oscillators with a line of equilibria

Nonlinear Dynamics - A model of memristor-based Chua’s oscillator is studied. The considered system has infinitely many equilibrium points, which build a line of equilibria. Bifurcational...     

Diagnostics of the degree of noise influence on a nonlinear system using relative metric entropy

In this paper we summarize and substantiate the relative metric entropy approach introduced in our previous papers [1, 2]. Using this approach we study the mixing influence of noise on both regular and chaotic systems. We show that the synchronization phenomenon as well as stochastic resonance decrease, the degree of mixing is caused by white Gaussian noise.     

Chimera states in ensembles of bistable elements with regular and chaotic dynamics

We consider ensembles of bistable elements with nonlocal interaction. It is shown that the bistability of units in the case of nonlocal interaction leads to the formation of chimera structures of a special type, which we have called double-well chimeras. Their distinctive feature consists in the formation of incoherence clusters with an irregular distribution of elements between two attractive sets existing in an individual element (two “potential wells”). Ensembles of different bistable units are considered, namely ensembles of cubic maps, FitzHugh–Nagumo oscillators in the regime of two stable equilibrium points and Chua’s circuits. The spatiotemporal behavior of the ensembles is studied in the cases of regular and chaotic dynamics in time, and different types of chimera structures are revealed.     

Mechanism of solitary state appearance in an ensemble of nonlocally coupled Lozi maps

We study the peculiarities of the solitary state appearance in the ensemble of nonlocally coupled chaotic maps. We show that the nonlocal coupling and features of the partial elements lead to the emergence of multistability in the system. The existence of solitary state is caused by the formation of two attracting sets with different basins of attraction. Their evolution is analyzed depending on the coupling parameters.     

Effect of noise on the relaxation to an invariant probability measure of nonhyperbolic chaotic attractors

We study the influence of external noise on the relaxation to an invariant probability measure for two types of nonhyperbolic chaotic attractors, a spiral (or coherent) and a noncoherent one. We find that for the coherent attractor the rate of mixing changes under the influence of noise, although the largest Lyapunov exponent remains almost unchanged. A mechanism of the noise influence on mixing is presented which is associated with the dynamics of the instantaneous phase of chaotic trajectories. This also explains why the noncoherent regime is robust against the presence of external noise.     

The electron energy loss spectrum of LiF in the band gap region

The eels of LiF has been measured in the range 0–18 eV with primary beam energies 50 eV and 1.5 keV. Four peaks are clearly resolved in the band gap region at room temperature. The amplitude of the three lower energy loss peaks was found to depend on beam exposure and temperature. It is concluded that the lowest energy peak arises at a beam induced defect, that the next two peaks arise in lithium metal liberated by the electron beam and that the peak nearest to the band edge is due to an intrinsic surface excitation.     

Inducing and destruction of chimeras and chimera-like states by an external harmonic force

We study the phenomena of chimera destruction and inducing of chimera-like states in an ensemble of nonlocally coupled chaotic Rössler oscillators under an external harmonic force. The localized harmonic influence can lead to both destruction and changing of the spatial topology of chimeras. At the same time this influence can cause the emergence of stable chimera-like states (induced chimeras) for the regime of partial coherent chaos. Induced chimeras are also observed for the global influence. We show the possibility of controlling the chimera-like state topology by varying the parameters of localized external harmonic influence.