Innovations in Applied Physics

Yttrium iron garnet (YIG) films on silicon substrates (Si) are of a great interest due to compatibility of their fabrication with semiconductor technologies and, thus, possible integration of magnonic and electronic devices on one chip. However, features of spin wave propagation in YIG films on semiconductor substrates remain almost unexplored.

We study gyrotron frequency locking by the external monochromatic wave and stabilization of gyrotron frequency by the wave reflected from the non-resonant or resonant load. Although in the last decades influence of the external monochromatic signal and the reflected wave at the gyrotron operation was studied in a number of publications, concrete schemes of gyrotron frequency stabilization weren’t discussed.

A paper presents the main stages of relativistic magnetrons’ development. We describe the designs eliminating conventional magnetrons’ shortcomings and restrictions which are associated with a radial output of radiation through a narrow slot in one of the magnetron resonators. A low breakdown threshold and an operation in only nondegenerate modes are among these restrictions.

Resistive wall amplifier is a vacuum microwave device, which has not been spread, but attracts attention again. Main features – no need to slow-wave structure and almost complete lack of feedback between output and input. The amplification occurs due to the phase shift between the electron beam and field variables that arise due to the presence of absorbing walls.

Terahertz-range backward wave oscillator – carcinotrons and klynotrons are widely used in radioelectronics systems for solving fundamental and applied problems. Instability of the output signal frequency of the said lamps is not worse than 10−4.

A method for gyrotron cathode treatment by flow of potassium ions has been developed, and the effect of ion bombardment on the emission characteristics of W-Ba and LaB6 cathodes has been investigated. The influence of cathode surface material, cathode emission activity and ion energy on the result of ion treatment was revealed. It was shown that ion bombardment can be used for the increase of cathode emission uniformity due to the activation of the W-Ba cathode areas with low electron emission and due to the deactivation of the LaB6 cathode areas with high electron emission.

Three-dimensional electromagnetic numerical simulation is carried out of «squeezed» state of the electron beam in two-section vircator system with drift tubes of different diameters. We have studied the influence of two-section system geometric parameters on the nonlinear dynamics of electron beam. We have obtained an effective plasma frequency depending on the system parameters.

Theoretical description of the Pockels effect is offered in which statement of a problem in the form of Maxwell equations allows to go on to wave equations directly and to find their solutions. Analytical expressions determining phase velocities and polarization of the optical plane waves, propagating in crystal of lithium niobate in principal crystallographic directions, for different cases of influence of an exterior static electric field are gained.

Processes in backward wave oscillator in pregeneration mode have been considered in the frame of two-dimensional theory. Spectral density dependencies on the relative transit angle are presented. The influence of magnetic field and space charge on its behavior has been analyzed.

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This work presents results of experimental research of chaotic signal wide-band generator based on UHF band TWT amplifier. Two generation methods of chaotic pulses sequences were investigated.

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