Izvestiya of Saratov University.
ISSN 1817-3020 (Print)
ISSN 2542-193X (Online)

Радиофизика, электроника, акустика

Effect of the finite conductivity of a metal on properties of a magnetostatic backward volume wave in layered metallized structures

Background and Objectives: Layered structures based on ferrite and metal films are actively studied in magnonics. Usually, the effects associated with the finite conductivity of the metal are not taken into account. The aim of this work was to investigate the influence of the thickness of a metal with finite conductivity on the dispersion and damping of a magnetostatic backward volume wave (MSBVW) in the ferrite-metal and ferrite-insulator-metal structures.

Analysis of three non-identical Josephson junctions by the method of Lyapunov exponent charts

Background and Objectives: The Josephson effect is widely used for both generating and receiving very high frequency signals. The approaches and methods of nonlinear dynamics are commonly used: construction of phase portraits, bifurcation analysis, Kuramoto model approach, etc. Usually large arrays of identical junctions are considered. However, the non-identity of junctions leads to new and interesting effects. A very popular model is a chain of junctions connected via an RLC circuit.

High-dimensional discrete map based on coupled quasi-periodic generators

Background and Objectives: Quasi-periodic oscillations are widespread in nature and technology. In the phase space, quasi-periodic oscillations with a different number of incommensurable frequencies correspond to invariant tori of different dimensions. Multiparametric analysis of high-dimensional systems is quite difficult. The way out of this situation can be the transition from systems with continuous time to discrete maps.

Simulation of turbulent gas flow

Background and Objectives: The purpose of the study carried out in the article is to obtain analytical expressions for calculating the gas (liquid) flow rate in the turbulent gas (liquid) flow regime. A method is presented for the mathematical description of a three-dimensional profile (hodograph) of the flow velocity in a turbulent flow regime based on two known velocity values in the pipeline cross section. The article analyzes the physical processes occurring in the turbulent flow.

Control of collective dynamics in multiplex networks of bistable time-delayed feedback oscillators with switched couplings

Background and Objectives: The study of complex collective dynamics in networks of coupled oscillators and its control is an important task for many scientific disciplines. Networks of nonlinear oscillators are capable of demonstrating a wide variety of spatiotemporal regimes of collective dynamics.

Modeling battery systems – problems of nonlinearity, efficiency, aging, coupling, and network setup

We discuss several problems of batteries and fuel cells from the point of view of nonlinear dynamics and review some earlier work on modeling this class of systems as well as new developments. We consider batteries and fuel cells as active nonlinear electrochemical circuits with properties depending on many factors as load, age, load history etc. We show that most satisfactory battery regimes are reached by coupling of an odd number of circuits in opposite phases.