ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)

Bifurcations in Dynamical Systems

Bifurcation analysis of synchronization and amplitude death in coupled generators with inertial nonlinearity

The results of analysis of bifurcation transitions to synchronous regimes and amplitude death are discussed for two dissipatively coupled generators with inertial nonlinearity. It was determined that there are two types of synchronization regions in this system: first consists of both frequency lock and suppression areas, second has only frequency lock area. At the weakly non-identical excitement parameters the first-type synchronization regions merge together.

Bifurcations and oscillatory modes in complex system with phase control

The results are produced of research of dynamical modes and bifurcation in a complex system with phase control, based on mathematical model with two degrees of freedom in the cylindrical phase space. The location of domains corresponding to different dynamical states of the system is established. The processes developing in the system as a result of loss stability of the synchronous mode, and scenarios of evolution of nonsynchronous modes under variation of system parameters are investigated.

Regular and chaotic dynamics of two-ring phase locked system. Part 2 - Peculiarities of nonlinear dynamics of frequency-phase system with identical third-order filters in control circuits

The results of investigation of dynamical modes in the model of oscillatory system with  frequency-phase control using multi-frequency discriminator inversely switched inthe chain of  frequency control are presented. The study was carried out on the basis of mathematical model of  the system with two degrees of freedom with the use of qualitative and numerical methods of nonlinear dynamics. It is shown that in such a system may be realized both synchronous and great  number of non-synchronous periodic and chaotic modes of different complexity.

Bifurcations in active predator – passive prey model

Bifurcations were studied numerically in the system of partial differential equations, which is  a one variant of predator-prey models. The mathematical model takes into account spatial  distribution in habitat, active directed predator movements, birth and death process in prey  population. The analysis of possible population dynamics development was performed by two  qualitatively different discrete sampling techniques (Bubnov–Galerkin’s method and grid method).

Analysis of noise­induced bifurcations for the Hopf system

We consider the Hopf system as a classical model of a stiff birth of a cycle. In the presence of parametrical and additive random disturbances, various types of the stochastic attractors are observed. The solution of the corresponding Fokker–Planck–Kolmogorov equation is found. The qualitative changes of the form for stochastic attractors under multiplicative noise are shown. The phenomenon of backward stochastic bifurcations is described in details.

Stochastic sensitivity of equilibrium and cycles for 1D discrete maps

The response problem of equilibrium and cycles for stochastically forced Verhulst population model is considered. Theoretical and empirical approaches are used for stochastically sensitivity analysis. The theoretical approach is based on the firth approximation method and the empirical approach is based on direct numerical simulation. The correspondence between the two approaches for Verhulst population model is demonstrated. The increase of discrete system sensitivity to external noise in the period­doubling bifurcation zone under transition to chaos is shown.

Bifurcations of a two-­dimensional torus in piecewise-­smooth dynamical systems

Considering a set of coupled nonautonomous differential equations with discontinuous right-hand sides, we discuss two different scenarios for torus birth bifurcations in piecewise-smooth dynamical systems. One scenario is the continuous transformation of the stable equilibrium into an unstable focus period-1 orbit surrounded by a resonant or ergodic torus.

On the way towards multidimensional tori

The problem of the dynamics of three coupled self-oscillators and three coupled periodically driven self-oscillators is discussed, in the last case only one of the oscillators is directly exited by the external fore. The regions of complete synchronization, two-, threeand four-frequency tori and chaos are revealed. Three typical situations of synchronization of three self-oscillators by the external driving are found. First situation refers to the mode locking of autonomous oscillators.

Experimental study of stochastic phenomena in a self­sustained oscillator with subcritical andronov–hopf bifurcation

The effect of noise on the self­sustained oscillator near subcritical Andronov–Hopf bifurcation is studied in numerical and full­scale experiments. Van der Pol oscillator is chosen as base model for investigation. The influence of both additive and multiplicative Gaussian white noise is considered. The regularities of evolution of the probability distribution in the self­sustained oscillator are analyzed with increase of the noise intensity for the cases of additive and parametric noise.

Noise-induced bifurcations in bistable oscillator

We investigate bistable oscillator under the influence of additive, white and colored, noise. We have found noise-induced bifurcations that consist in a qualitative change of stationary distribution of oscillations amplitude. In the region of bimodal distribution the effect of coherent resonance takes place both for white and colored noise.