A. V. Dormidontov

Auto-oscillation system based on dielectric resonator with “Whispering gallery” modes

A new method of microwave generation in a system with high-Q quasi-optical cylindrical dielectric resonator (CDR) excited by an azimuthal-periodic electron beam current is proposed. Characteristic parameters of a cylindrical fluoroplastic CDR have been determined. Data on microwave generation in a system based on a CDR with whispering-gallery eigenmodes excited by a relativistic azimuthal-periodic electron beam current are presented. Electromagnetic radiation of this system was measured using a detector for the 8-mm wavelength range.

Fast charge energy losses in structures with a 2D electron gas

Fast charge energy losses for the excitation of natural oscillations in media with a 2D plasma sheath are studied. A semiconducting (dielectric) cylinder-2D plasma sheath-vacuum system is considered. Dispersion relations describing natural oscillations in such a system are derived. Energy losses of a point charge rectilinearly and uniformly moving over and inside the cylinder are found. The loss of energy by a moving charged ring embracing the system (specifically, a nanotube) is considered.

Eigen frequencies of cylindrical structures with a plasma sheet

The dispersion equations that describe eigen modes of the semiconductor and dielectric cylinders with a plasma sheet on a lateral surface are obtained. The dispersion dependences of eigen slow waves in such system based on analytical and numerical approaches are obtained. The structures both with a plasma sheet and without it, for which eigen frequencies are in the terahertz range, are studied. The comparison of frequency spectrums of eigen modes of studied systems is made. The influence of a surface plasma sheet with a thickness of atomic size on the eigen frequencies of the semiconductor and dielectric cylinders with modes of identical field distributions is studied.

Energy losses analysis of charged particle moving in inhomogeneous medium

Energy losses of a charged particle moving along a spiral path above the surface of a dielectric or metal cylinder were determined using Maxwells equations. The conditions of gyrosynchrotron radiation of electromagnetic waves in the system were formulated. Obtained results are important for understanding of generation mechanisms of electromagnetic waves in electrodynamic systems that are the basis of microwave oscillators.

The energy loss of high-velocity charges in the structures with two-dimensional electron gas

The energy loss of high-velocity charges at the excitation of eigen modes in mediums containing two-dimensional plasma layer were studied. The following structures were studied: semiconductor (or dielectric) cylinder-plasma layer-vacuum. The corresponding dispersion equations describing eigen modes of these systems were obtained. The energy loss of the point charge moving linear and uniformly above cylinder or inside it were found. The features of energy loss of the moving charged ring covering the structure, particularly nanotube, were studied.

The effect of ambient temperature on eigenfrequencies of a quasi-optical cylindrical dielectric resonator

Effects of the temperature and refractive index of ambient air on the eigenfrequencies of a cylindrical dielectric resonator (CDR) featuring whispering-gallery modes have been studied. An attempt to separate the effects of two factors on the spectral and energy characteristics of a fluoroplastic CDR for a millimeter wavelength range has been made for the first time. It is established that the behavior of CDR eigenfrequencies and the stability of Q factors exhibit different characters when the temperature is varied from −60 to +60°C and the permittivity of air is changed from 1 to 1.0004. A CDR can be used as a sensor of ambient temperature accurate to within 10−4 K, provided that the resonance frequencies in the millimeter wavelength range are measured to within 1 kHz.

Spectrum of dielectric spherical resonator forced by azimuthally periodical electrical current

Spectral characteristics of an isotropic spherical dielectric resonator placed into isotropic medium forced by azimuthally periodical electrical current that flows in the sphere equatorial plane is studied. It is shown that this current excites E and H modes. If the frequency of ring current radiation coincides with the frequency of eigenmode there is an amplitude resonance in oscillating system.