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

Innovations in applied physics

About periodic interaction of two electron streams between themselves and with fields of electrodynamics systems

In this paper, brief review of new and early publications devoted to the interaction of electron streams and the enhancement due to the interference of partial waves in streams, and due to instability is adduced. The lay emphasis on the consideration the mechanism of periodic interaction of electron streams as applied to option of the variant double-stream traveling-wave tube, on the example of system consisting of two electron beams divided by the metallic perforated screen, which interact with the electromagnetic field.

Study of miniaturized low-voltage backward-wave oscillator with a planar slow-wave structure

The development of the terahertz frequency range is one of the priority problems of modern vacuum microwave electronics. For increasing power and efficiency of such devices, it is favorable to use spatially developed slow-wave structures (SWSs) and electron beams with a large cross section. For miniaturization of vacuum-tube devices, reducing of the accelerating voltage becomes a problem of principal importance. In this respect, planar SWSs on dielectric substrates are very promising.

Nonlinear dynamics of spin waves in lateral magnetic microwaveguides

In the present work, a numerical and experimental study of the nonlinear dynamics of spin waves in lateral magnetic microwave guides was made. The mechanism of nonlinear spin-wave coupling between different types of modes in lateral waveguides was revealed. The investigation of lateral magnetic microstructures supporting both linear and nonlinear propagation of spin waves is of great interest nowadays.

Transformation of eigenmodes spectrum of finite width multiferroic structure due to tuning of the gap between ferrite and ferroelectric layers

We consider a layered multiferroic structure consists of laterally confined ferrite and ferroelectric layers. We study the influence of the air gap between the layers on properties of transverse modes of hybrid waves. By the solution of the electrodynamic problem with the finite element method we show that with increasing of distance between the ferrite and ferroelectric layer the coupling between the waves of these partial systems weakened. These results can be used to explain the experimental data obtained on the layered structure.

Non-additive influence of water vapor and lighting on the conductivity of tin dioxide film at room temperature

Subject and purpose of the study. The paper presents the results of experimental studies of the effect of water vapor and light intensity on the conductivity of a thin film of tin dioxide at room temperature. It is known that the use of illumination of active layers of sensors allows to reduce their operating temperature, which expands the application field of sensors and multisensor systems based on them. The aim of the paper is to investigate the joint influence of lighting and the effect of water vapor on the conductivity of tin dioxide films. Methods and materials.

Nonlinear spin-wave propagation in the nonidentical magnonic structures

Topic. Investigation of nonlinear propagation modes of a spin-wave signal in lateral non-identical structures, taking into account the multi-mode spin waves. Aim. Consideration of the effect of intermode coupling on the intensity distribution of surface magnetostatic waves propagating in lateral waveguides of various widths. Identify the possibility of changing the coupling coefficient by varying the power of the input signal. Methods.

Study of synchronization in the system of two delay-coupled gyrotrons using a modified quasilinear model

Topic. The paper is devoted to the study of mutual synchronization of two gyrotrons coupled with delay. As a rule, a theoretical study of synchronization of gyrotrons and other microwave oscillators is usually carried out by numerical simulations using certain well-established models of microwave electronics. Using this approach, it is difficult to provide a fairly complete synchronization pattern, using methods and ideas of nonlinear dynamics. Aim.

Hyperbolic chaos in the Bonhoeffer–van der Pol oscillator with additional delayed feedback and periodically modulated excitation parameter

Topic and aim. The aim of the work is to consider an easy-to-implement system demonstrating the Smale–Williams hyperbolic attractor based on the Bonhoeffer–van der Pol oscillator, alternately manifesting a state of activity or suppression due to periodic modulation of the parameter by an external control signal, and supplemented with a delayed feedback circuit. Investigated models. A mathematical model is formulated as a non-autonomous second-order equation with delay. The scheme of the electronic device that implements this type of chaotic behavior is proposed.

Noise in resistive-wall amplifier of m-type with «thick» beam

The aim of our research is to study the noise in the resistive-wall amplifier with crossed electric and magnetic fields with a beam of finite thickness. The theory of the O-type resistivewall amplifier is well known, at least as a classical example of using of waves with negative energy. Theory of resistive-wall amplifier M-type, in which negative energy waves are also used, has not been studied until recently. It seems interesting to study noise in a device with crossed fields, especially since early work mentioned a possible low noise level. Method.