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卷 58, 编号 11 (2016)

Article

Propagation and Generation of Electromagnetic Waves at Proton Gyrofrequencies in a Relativistic Electron–Positron Plasma. II. Excitation of Electromagnetic Waves

Zheleznyakov V., Bespalov P.

摘要

In part I of this work [1], we study the dispersion characteristics of low-frequency waves in a relativistic electron–positron plasma. In part II, we examine the electromagnetic wave instability in this plasma caused by an admixture of nonrelativistic protons with energy comparable with the energy of relativistic low-mass particles. The instability occurs in the frequency band between the fundamental harmonic of proton gyrofrequency and the fundamental harmonic of relativistic electron gyrofrequency. The results can be used for the interpretation of known observations of the pulsar emissions obtained with a high time and frequency resolution. The considered instability can probably be the initial stage of the microwave radio emission nanoshots typical of the pulsar in the Crab Nebula.

Radiophysics and Quantum Electronics. 2016;58(11):807-815
pages 807-815 views

A Study of Interaction of an Electron Beam with a Strong High-Frequency Field in the Waveguide Switch of a High-Power Microwave Compressor

Lobaev M., Ivanov O., Vikharev A., Gorbachev A., Isaev V.

摘要

We present the results of simulating numerically the operation of a high-power active compressor of microwave radiation pulses in the 3-cm wavelength band with a waveguide switch activated by an electron beam. The influence of the nonlinear character of electron beam interaction with the high-frequency field in the switch on the output parameters of the compressor is discussed, and the simulation results are compared with the experimental data. It is shown that at a high power of the input radiation, the effect of electron expulsion from the region of the inhomogeneous field in the switch can lead to a decrease in the compressor gain and elongation of the leading front of the compressed pulse.

Radiophysics and Quantum Electronics. 2016;58(11):816-824
pages 816-824 views

Control of the Radial Energy Deposition Profile in an Open Magnetic Trap During Electron Cyclotron Plasma Heating

Gospodchikov E., Smolyakova O.

摘要

We propose a method for controlling the radial profile of electron cyclotron plasma heating in an axisymmetric magnetic mirror by using minor perturbations of the magnetic field of the mirror. The method is based on the analysis of the ray trajectories behavior near the surface of the electron cyclotron resonance. A way to produce such perturbations by supplementing the system with an additional “quadrupole” pair of magnetic coils is also proposed. The possibility to improve the coupling of radiation with the plasma in an open trap is demonstrated, as well as the possibility to control the energy deposition profile by means of small variations of the current in the additional coils for two basic scenarios of electron cyclotron plasma heating, specifically, longitudinal launching of microwave radiation to the magnetic mirror region and trapping of obliquely launched radiation by the inhomogeneous magnetized-plasma column.

Radiophysics and Quantum Electronics. 2016;58(11):825-835
pages 825-835 views

The First Russian Orbit-Borne Scatterometer: Numerical Simulation

Karaev V., Panfilova M., Titchenko Y., Meshkov E., Balandina G., Kuznetsov Y., Shlaferov A.

摘要

We have chosen a “SeaWinds” scatterometer with an orbital altitude of about 800 km as a prototype of the first Russian orbital scatterometer. An involuntary decrease in the orbit altitude to 650 km made us choose between conservation of the initial swath width 1800 km or the incidence angles with the swath-width decrease to 1500 km. A wider swath width has the advantage of a better coverage of the world-ocean surface. However, it leads to an increase in the local incidence angles and, hence, a decrease in the reflected-signal power. As a result, the signalto-noise ratio decreases and an error in the wind velocity and direction reconstruction because of the equipment noise increases. The error of the wind-velocity vector reconstruction for the same drive and antenna is the choice criterion. During the study, the mathematical model of the scatterometer is developed, the numerical simulation for both swath widths is performed, the data are processed, and the reconstruction accuracies of the wind velocity and direction are compared. It is shown that the reconstruction accuracy can significantly be improved if the measurement for two polarizations is used. The results obtained also show that the wind velocity is sufficiently well reconstructed for both swaths, while the wind-direction reconstruction accuracy in the case of a wider swath is worse than that required by the technical specifications for the scatterometer. Therefore, the swath width of the new scatterometer should be 1500 km.

Radiophysics and Quantum Electronics. 2016;58(11):836-851
pages 836-851 views

Frequency Spectrum of Exact Solutions of the Two-Dimensional Hydrodynamic Equations

Abrashkin A., Yakubovich E.

摘要

We show that the discrete frequency spectrum of a plane hydrodynamic flow of ideal incompressible liquid with localized trajectories of the liquid particles can contain only one, two, or an infinite number of harmonics.

Radiophysics and Quantum Electronics. 2016;58(11):852-857
pages 852-857 views

Integration of the Equations of Classical Electrode-Effect Theory with Aerosols

Kalinin A., Leont’ev N., Terent’ev A., Umnikov E.

摘要

This paper is devoted to an analytical study of the one-dimensional stationary system of equations for modeling of the electrode effect in the Earth’s atmospheric layer with aerosols. New integrals of the system are derived. Using these integrals, the expressions for solutions of the system and estimates of the electrode layer’s thickness as a function of the aerosol concentration are obtained for numerical parameters close to real.

Radiophysics and Quantum Electronics. 2016;58(11):858-867
pages 858-867 views

Adaptive Matching of the Scanning Aperture of the Environment Parameter

Choni Y., Yunusov N.

摘要

We analyze a matching system for the scanning aperture antenna radiating through a layer with unpredictably changing parameters. Improved matching has been achieved by adaptive motion of a dielectric plate in the gap between the aperture and the radome. The system is described within the framework of an infinite layered structure. The validity of the model has been confirmed by numerical simulation using CST Microwave Studio software and by an experiment. It is shown that the reflection coefficient at the input of some types of a matching device, which is due to the deviation of the load impedance from the nominal value, is determined by a compact and versatile formula. The potential efficiency of the proposed matching system is shown by a specific example, and its dependence on the choice of the starting position of the dielectric plate is demonstrated.

Radiophysics and Quantum Electronics. 2016;58(11):868-876
pages 868-876 views

Dynamics of the Phase Oscillators with Plastic Couplings

Kasatkin D., Nekorkin V.

摘要

We study the dynamical regimes in the system of two identical interacting phase oscillators with plastic couplings. The joint evolution of the states of the elements and the interelement couplings is a feature of the system studied. It is shown that the introduction of plastic couplings leads to a multistable behavior of the system and emergence of the asynchronous regimes which are not observed for the considered parameter values in the case of static couplings. The parameter plane is divided into regions with different dynamic regimes of the system. In particular, the regions in which the system demonstrates bistable synchronous behavior and the region in which the coexistence of many various asynchronous regimes is observed are singled out.

Radiophysics and Quantum Electronics. 2016;58(11):877-891
pages 877-891 views