Application of Krylov-Bogolyubov averaging method to the problem of periodic perturbations in the layered medium

Influence of small periodic perturbation in periodic dielectric medium on propagation of ТМ-polarized waves is investigated by the Krylov-Bogolyubov averaging method. As a result of periodic perturbation inside the allowed bands of unperturbed medium forbidden bands appear. The appearance of forbidden bands is conditioned by a parametric resonance between spatial harmonics of perturbation and plane waves, on which the solution of the wave equation in periodic medium is decomposed. The location, number and width of these bands are determined

Plasma sphere equilibrium in external r.f. fields

The problem on confinement and equilibrium of the spherical plasma formation in external r.f. electromagnetic fields is solved using the method of the integral equation of macroscopic electrodynamics. Namely, the problem of plasma confinement with r.f. pressure forces (the Gaponov-Miller force) is formulated and self-consistent problem of the external electromagnetic field providing the required configuration of non-disturbance electromagnetic fields e.g. the field in which together with volume charge forces taken into account forms the spherical symmetric potential well is solved. It is shown that such a solution exists only if there is rotating ordered motion of plasma. It is naturally that the non-disturbance confining r.f. field is determined only in the region linear dimensions of which correspond to the sphere ones. The field value out of these dimensions is defined solving the corresponding non-corrected mathematical problem. This permits to build the source of the confining field with the definite arbitrariness that makes easier to realize the device in practice

The thin structure of waveguide dielectric accelerating system elements

Last years the works appeared in which models of artificial dielectrics containing in a frequency band simultaneously negative values of the dielectric permittivity and magnetic permeability were discussed [1, 2]. As is shown in [3], the electromagnetic wave propagation in such a media is characterized with peculiarities that are important to understand the electromagnetic radiation interaction with tissues in vivo. The aim of this work is to show that such a media in organic nature can be meet at every step, and the mechanism of formation of simultaneous negative values of ε(ω) and μ(ω) is contained already by their physical structures. Moreover, experimental facts are known confirming the existence of positive and negative values of ε and μ in a narrow frequency band that, unfortunately, is still not completely understood till now

Integrated tuning of dielectric elements of accelerating structures

The method based on a longitudinal waveguide dielectric resonance for tuning dielectric elements of slow-wave structure cells is reported. The cells with dielectric disks are tuned by compensating the permittivity spread and technological tolerances through the selection of the dielectric disk width. The method provides tuning of disks in the cells to accuracy no worse than 0.01 MHz for the general working frequency of the structure. This method is applicable for determining integrated characteristics of dielectric elements (effective permittivities) in microwave devices that can be used, for example, for the development of exit windows for high power microwave flows

Efficiency of linear accelerators for applied aims

As it is well known the accelerator efficiency as a whole η is the product of the efficiency of an accelerator itself ηa and the efficiency of its power feed system ηf : η = ηa ∙ ηf. There are many papers in which the value of ηa is considered but the value of ηf is studied worse. This paper is the review of the works concerning the increase of ηf in dependence on a chosen high-frequency power system of the accelerator. In this case both linear electron accelerators and proton radio-frequency accelerators are considered. In initial versions the accelerator was considered as a system consisting of two subsystems: i.e. the power supply system and the accelerating structure itself. It was supposed that ηf is determined by a product of the generator efficiency multiplied by the feeding system efficiency. Separately created was r.f. generator with a high electronic efficiency and the feeding system was improved. Last time the tendency appeared when the feeding system was degenerated practically and r.f. power system of the accelerator was the component structure of the accelerator itself. Let consider the evolution of r.f. power system on examples of electron and proton accelerators

Research of waveguide accelerating structures with dielectrics

At a choice of slow-wave structure for application in accelerating technique the main attention is given first of all to its two characteristics: 1) opportunity of use of a partial type of structures in the wider range of energies and 2) the transformation efficiency of high-frequency energy, put to structure, into a kinetic energy of accelerated particles, that eventually leads to comparison of structures on shunt impedance. From this point of view, the waveguides loaded by dielectric disks have doubtless advantages before other traditionally used structure

Study of a biperiodic slow-wave structure at medium energies

In the present work charged particle accelerators occupy the important place both in scientific, and in practical applications

Disposal of radioactive waste by means of nuclear conversion

Nowadays radioactive waste (RW) are being buried in geologic rocks. There is an alternative method of waste disposal. It is a transmutation of radioactive isotopes into stable ones by nuclear reactions with the use of accelerators with a particle energy of 50-1000 MeV. We have shown that neutrons from spallation reactions have no advantages in comparison with a hard neutron spectrum reactor technology. We have shown that during reprocessing the Th-U reactor RW, where there is a lack of actinide group, the effectiveness of proton beams and neutrons from the spallation reaction for RW disposal may be at the required level