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

Innovations in applied physics

Dynamics of cylindrical electron beams injecting in a half-space with perfectly-conducting boundary

The purpose of this work is to study the dynamics of electron beams and bunches in a system with an ideally conducting plane and a uniform magnetic field in the presence of delayed electromagnetic waves when a virtual cathode is formed in the system and with parameters close to this state. Methods. The dynamics of a cylindrical electron beam flying through an ideally conducting plane into a strong longitudinal magnetic field is studied by numerical simulation. Particles are large.

Numerical simulation of magnetostatic waves propagation in coupled meander-type magnon crystals

Purpose of the work is to generalize the results of numerical studies for coupled magnonic meander structures in the case of the propagation of various types of magnetostatic waves in such structures. Methods. In order to solve the problems two well-known methods were used – finite elements and finite differences for coupled ferromagnetic structures. For the numerical solution with the finite element method in the magnetostatic approximation, the magnetostatic equations derived from Maxwell’s equations were used.

About nonlinear theory of two-cavity klystron with a drift space in the form of medium with complex permittivity

The purpose of this work is to construct an approximate nonlinear theory of a klystron amplifier in which a medium with complex conductivity or with metamaterials with negative permittivity is located between the input and output cavities instead of the drift space. Within the framework of the constructed theory, calculate the output characteristics (gain, output power and efficiency) of the described device and compare the results with the classic two-cavity klystron. Methods.

The effect of various electrodes on the character of the course of chemical oscillating reactions Briggs–Rauscher

Purpose of the present study is to determine the sensitivity of chemical self-oscillating reactions to various types of electrodes: silver chloride electrode, carbon electrode, platinum electrode. Methods.

Micromagnetic modeling of nonlinear interaction of lateral magnetostatic modes in cross-shaped structures based on waveguides from iron yttrium garnet films

Topic. In this work, parametric processes in the system of predominantly dipole magnetostatic waves (MSW) in the cross-shaped structure from two orthogonal waveguides of iron yttrium garnet film magnetized by the in-plane field H = 460 Oe and having microstrip transducers at its ends are considered. One of the antennas at the end of the transversely magnetized waveguide was assumed as an input and was used to excite MSW with the frequency of 3 GHz. Aim.

Zones of stable single-mode generation in overmoded gyrotrons

During numerical simulations of the model of gyrotron with fixed field-structure, zones of stable single-mode generation of the work mode are analyzed on the plane of parameters «magnetic field – beam current». It is shown that area and sizes of the zones are strongly dependent on the spectral density of eigen-frequencies of the resonator and on number of considered parasit modes.

Methods of output power increasing in orotron with double- row periodic structure in the short-wavelength part of millimeter-wave range

The peculiarities of the orotron double-row electrodynamical system and methods of output power increase were investigated. For the first time in the experimental model of orotron with electrodynamical system consisting of double-row plain periodic structure (DRPS) and sphere-cylindrical focusing mirror the possibility of using wide electron beam in order to output power increase in 140...300 GHz frequency range is demonstrated.

Two-wave gyrotron on whispering gallery modes at the irregular waveguide

The three-dimensional excitation equations for the longitudinal-irregular circular waveguides with finite conductions of the walls by electron beams in completed form for self-consistent models of gyrotrons, peniotrons, relativistic TWT and BWO had been derived. The possibilities of improving the efficiency of millimeter-wave gyrotron with multimode interaction fields of whispering gallery waves and a relativistic helical electron beam were consider. It is shown that two-mode gyrotron, compared with single-mode allows you to raise the efficiency from 40 to 45%.

Ohmic loss calculation in the open resonators

We present a numerical method for calculation the eigenmodes of the open resonator. We assume, that the resonator mirror has the finite conductivity. The new approach, based on the modified method of the field continuation, was suggested. The results obtained were compared with the asymptotic solution.

Accidental resonators

Anderson localization of electromagnetic waves incident on a disordered medium manifests itself in exponential decrease of the wave amplitude inwards the medium. Transparency of the medium is exponentially small if the medium thickness is large enough. However, there is a set of frequencies (resonances), specific for every random realization of the disordered medium, for which the medium is almost transparent. These sets are «fingerprints» of the media: every realization is characterized by its own unique set of resonances.