FOCUSING OF POSITRON BUNCH WHEN MOVING IN ELECTRON BUNCH WAKEFIELD IN THE DIELECTRIC WAVEGUIDE FILLED WITH PLASMA

The results of numerical PIC-simulation of focusing accelerated (test) positron and drive electron bunches in the dielectric waveguide filled with radially heterogeneous plasma with the vacuum channel are given in the paper. The wakefield was excited by electron bunch in quartz dielectric tube, inserted into cylindrical metal waveguide. The internal area of dielectric tube has been filled with plasma different transverse density profiles, heterogeneous on radius, with the vacuum channel along waveguide axis. Plasma density for all studied cases was so low that plasma frequency was less, than the frequency of the main dielectric mode. Results of numerical PIC simulation have shown that possibility of simultaneous acceleration and focusing of the test positron bunch are possible in the wakefield. The best acceleration happens in case of plasma absence, however at that there is no focusing of test positron bunch.

Plasma-electrolyte discharges in a gas-liquid medium for the production of hydrogen

THE PURPOSE. Comprehensive study of the effect of direct current electric discharge plasma in a gas-liquid medium of inorganic mixtures in order to obtain gaseous hydrogen. Obtain volt-ampere, volt-second and ampere-second characteristics of the discharge at various concentrations of electrolyte. Study the process of electrolysis, breakdown, discharge ignition and discharge flow in a dielectric tube at a constant current. METHODS. To solve this problem, experimental studies were carried out on a model installation, which consists of a power supply system, a discharge chamber, equipment for monitoring and controlling the operation of the installation and measuring the characteristics of an electric discharge. To analyze the stability of the discharge, the time dependences of the voltage ripple and the discharge current were obtained. RESULTS. Experimental studies were carried out between the electrolytic cathode and the electrolytic anode at constant current and at atmospheric pressure with the following parameters: discharge voltage U = 0.1-1.5 kV, discharge current I = 0.02-2.3 A, interelectrode distance l = 100 mm , 1%, 3% and 5% solutions of sodium chloride in tap water were used as electrolytes. CONCLUSION. It is shown that electrical breakdown and ignition of a discharge that is stable in time depends on the conductivity of the gas-liquid medium of the electrolyte. The nature of the current-voltage characteristics depends on the random processes occurring in the gas-liquid medium, which is associated with numerous breakdowns occurring in the gas-liquid medium of the electrolyte, combustion and attenuation of microdischarges, the appearance of bubbles, and the movement of the electrolyte inside the dielectric tube. It is shown that the generation of hydrogen and hydrogen-containing components can occur both at the stage of electrolysis and during discharge combustion. A feature of this method is that electrical discharges in the tube increase the release of hydrogen. In this installation, inorganic and organic liquids of a certain composition and concentration can be used. The results of experimental studies made it possible to develop and create a small-sized installation for producing gaseous hydrogen. Tests have shown that a small-sized plant can be taken as the basis for a industrial plant for the production of hydrogen gas.

Hybrid coupled mode modelling of the evanescent excitation of a dielectric tube by semi-guided waves at oblique angles

A dielectric step-index optical fiber with tube-like profile is considered, being positioned with a small gap on top of a dielectric slab waveguide. We propose a 2.5-D hybrid analytical/numerical coupled mode model for the evanescent excitation of the tube through semi-guided waves propagating in the slab at oblique angles. The model combines the directional polarized modes supported by the slab with analytic solutions for the TE-, TM-, and orbital-angular-momentum (OAM) modes of the tube-shaped fiber. Implementational details of the scheme are discussed, complemented by finite-element simulations for verification purposes. Our results include configurations with resonant in-fiber excitation of OAM modes with large orbital angular momentum and strong field enhancement.

Microwave Generated Plasma Railway Track Treatment

Braking conditions are a fundamental issue for the railway and have been a limiting factor in network capacity & timetabling. This work was focused on taking high power microwave generated plasma out of the laboratory into a railway environment. The Imagination Factory with no experience in microwave generated plasma has partnered with experts in this field to develop a mobile system which delivered 15kW 2.45GHz microwave generated plasma – Fig.1. The plasma was created within a dielectric tube placed in a monomode microwave cavity; the atmospheric plasma sustained in different inert gases (nitrogen, argon) gases as well as mixtures of inert gases with reactive molecules was jetted directly onto the railhead as to change the conditions for the wheel-rail interface. This technology is hoped to be a game changer in enabling predictable & optimized braking on the railway network. Challenges encountered during the demonstration phase will be discussed.

Development and justification of the parameters of the microwave installation for heat treatment of rejected chicken eggs

Russia ranks sixth in the world in egg production, with only 13% being processed. In addition, egg waste from incubation cabinets is also accumulated, which can be processed into protein feed using vacuum boilers. In this regard, the development of technology and technical means using the energy of the electromagnetic field of ultra-high frequency for heat treatment of rejected eggs in a continuous mode for farms is relevant. The aim of the research is to develop and substantiate the parameters of the microwave installation for heat treatment of rejected chicken eggs as a protein feed additive. Tasks are being solved: to develop a spatial model of a microwave installation of a continuous operation mode; calculate the construction parameters of the installation. The microwave installation developed contains a vertically mounted truncated non-ferromagnetic bicone. Along its inner side surface, a dielectric tube is laid in the form of a biconical spiral. Parallel to the vertical axis of the bicone, a non-ferromagnetic plate is installed, dividing its volume into two chambers: a resonator and a pause chamber. The plate is made in the form of an axial section of a truncated bicone, along the perimeter of which there are openings for transcendental waveguides worn on the dielectric tube from the pause chamber side. On the side surface of the bicone mounted magnetrons. The structural design of the installation ensures the continuity of the heat treatment process without transporting mechanisms. The calculated self-quality of the resonator is 5000. With an installation capacity of 18 kg/h, the specific energy consumption for heat treatment of eggs is 200 W.h/kg.