Sergey Kashchenko

This paper studies the dynamics of a system of two coupled self-excited oscillators of first order with on-off delayed feedback using numerical and analytical methods. Regions of “fast” and “long” synchronization are identified in the parameter space, and the problem of synchronization on an unstable cycle is examined. For small coupling coefficients it is shown by analytical methods that the dynamics of the initial system is determined by the dynamics of a special one-dimensional map.

Spatially distributed integro-differential systems of equations with periodic boundary conditions are considered. In applications, such systems arise as limiting ones for some nonlinear fully coupled ensembles. The simplest critical cases of zero and purely imaginary eigenvalues in the problem of stability of the zero equilibrium state are considered.
In these two situations, quasinormal forms are constructed, for which the question of the existence of piecewise constant solutions is studied. In the case of a simple zero root, the conditions for the stability of these solutions are determined. The existence of piecewise constant solutions with more than one discontinuity point is shown. An algorithm for calculating solutions of the corresponding boundary value problem by numerical methods is presented. A numerical experiment is performed, confirming the analytical constructions.