Innovations in Applied Physics

This article contains analysis of properties discrete electron-wave interaction in resonance slow-wave system (SWS). Equations of interaction are written in matrix form. Eigenvalues of transfer matrix with electron beam define spread constant of four electron waves. Features of electron waves in SWS with «smooth» energy stream and in SWS with «winding» flow are examined. Simulation is performed and amplification of multisection TWT with passband and stopband sections of SWS is found. Field distribution along stopband section is found.

The synthesis of carbon nanotubes is carried out on the surface of molybdenum substrates by CVD-method using thin-film iron and water solutions of ferritin and iron acetate as catalysts sources. It is found that the temperature of process technology in the synthesis of carbon nanotubes on molybdenum substrates must be above 900 ◦C. At this point, only non-uniform films of carbon nanotubes on the surface of molybdenum substrates were obtained.

The methods of field emitter durability growth while operating in technical vacuum conditions are developed in SPbSPU and are describing in this paper. Two possibilities to secure durable emitter operation are considered: using the special protective fullerene coatings and arrangement of new type of emitter where the fields of spots on the contacts of the materials with greatly different work function provide the field emission.

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.

The periodic structure consisting of a shallow grooves on a surface of a ferromagnetic film was investigated. The electrodynamical characteristics of propagation of the surface magnetostatic wave in this structure were obtained. The 2D model of the periodical Yttrium Iron Garnet structure was numerically studied by the algorithm based on the Finite Element method. The spatial distribution of the electric and magnetic field components in different points of dispersion characteristics was studied in detail. The comparison of experimental data and numerical results was carried out.

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. With increase of spectral density the point of highest attainable efficiency of stable single-mode generation shifts to the region of lower currents and simultaneously this value of efficiency decreases.