Study of the dependence of the transition energy $E_1+\Delta_1$, on the $Hg_{1-x}Mn_xTe$ composition by the electrorefiectance method
Study of the dependence of the transition energy $E_1+\Delta_1$, on the $Hg_{1-x}Mn_xTe$ composition by the electrorefiectance method
L.P. Avakyants, E.I. Veliyulin, A.A. Mamedov, A.V. Chervyakov
Electroreflectance spectra of $Hg_{1-x}Mn_xTe$ solid solutions were used to determine the coefficients of a polynomial that expresses the dependence of the transition energy $E_1+\Delta_1$ on the concentration parameter $x$. The possibility of local topographic investigations of the composition heterogeneity on the semiconductor surface is demonstrated.
Show AbstractA study of nonlinearity in the process of tsunami generation by sea floor motion
A study of nonlinearity in the process of tsunami generation by sea floor motion
0.V. Kostitsyna, M.A. Nosov, N.K. Shelkovnikov
The process of tsunami wave generation by motions of the sea floor with residual displacement has been investigated by numerical modeling. Fast, medium-velocity, and slow floor oscillations are considered. The role of nonlinear effects is estimated as a function of the magnitude of the sea floor displacement and oscillation duration in the cases of elevation and subsidence of a sea floor section. The experimental data are compared with the results of numerical experiments.
Show AbstractPyroelectric coefficient of the PZT-40 ceramics in the 1.5-80 K temperature range
Pyroelectric coefficient of the PZT-40 ceramics in the 1.5-80 K temperature range
A.B. Esengaliev, V.K. Novik, V.V. Novikov, A.G. Segalla
The pyroelectric coefficient was measured in the 1.5-80 K temperature range and the permittivity in the 1.5-250 K range for PZT-40 ferroelectric ceramics.
Show AbstractSolitons with few time or space periods
Solitons with few time or space periods
A.V. Vederko, 0.B. Dubrovskaya, V.F.Marchenko, A.P. Sukhorukov
The theory of solitons in a medium whose dispersion and nonlinearity are described by the Duffing equation, is discussed. A modified Korteweg-de Fries equation is derived for signals comprising a small number of oscillations under the envelope. The soliton and breather propagation is investigated. It is shown that as the number of periods increases, the breather turns into the envelope soliton. The process of formation and propagation of slow solitons in a cubically-nonlinear medium with a limited passband is considered for the case of two real physical systems (the waveguide and periodic structure}. Exact analytical expressions for the soliton shape are obtained and the region of their existence is indicated. The conditions for excitation of a nonpropagating soliton are discussed.
Show AbstractThree-dimensional mathematical models of RF electromagnetic fields
Three-dimensional mathematical models of RF electromagnetic fields
A.D. Grigor'ev, S.A. Silaev
Mathematical models of RF electromagnetic fields in a three-dimensional statement are described. The specific features of solving three-dimensional problems are discussed, including problems of increasing the accuracy and elimination of false solutions. Information is given on programs compiled in other countries for solving three-dimensional spectral problems; their comparative characteristics are presented. The algorithms and results of a numerical modeling for the ISFEL3D program compiled in Russia are described.
Show AbstractOn the possibility of generating coherent short-wave radiation with the aid of relativistic particles moving in crossed fields
On the possibility of generating coherent short-wave radiation with the aid of relativistic particles moving in crossed fields
A.N. Didenko
A generator of coherent short-wave radiation, called creditron, is proposed, which uses relativistic particles moving in trochoids in crossed electric and magnetic fields, and its physical foundations are described. It is shown that the wavelength of the generated radiation depends on the particle energy as in free electron lasers, but, in contrast to the latter, these installations can employ electron beams with wider energy scatter and lower density, i.e., beams, which arc currently available. The effect of the Coulomb field and the possible methods of particle focusing in such installations are considered.
Show AbstractElectron interaction energy in relativistic O-type devices
Electron interaction energy in relativistic O-type devices
A.A. Kuraev, N.A. Kuraev, A.K. Sinitsyn
Allowance for the space charge in relativistic microwave O-type devices encounters difficalties because of the absence of a rigorous theory of interaction of an ensemble of relativistic charged particles in nonuniform motion. A simplest model (thin relativistic electron beam (REB) without regard for thin metallic walls) has been employed to study electron grouping in the drift region and the amplification process in a traveling-wave tube of O-type (TWT-O) with irregular decelerating system. It is shown that: (a) During electron grouping, part of the REB energy is accumulated in the bunch in the form of interaction energy, which does not coincide with the relativistic potential energy and, for currents of the order of 200 A, attains 6 to 10% of the total REB energy; (b) The interaction energy leads to a TWT-O efficiency loss of the order of 10%; (c) The correction for the nonuniformity of the electron motion is insignificant, and, consequently, Lorentz' transformations can be used in the calculation of forces of the spatial charge in O-type devices.
Show AbstractGuiding and superradiance effects in ensembles of electrons-oscillators
Guiding and superradiance effects in ensembles of electrons-oscillators
N.S. Ginzburg, A.S. Sergeev
The induced emission of localized ensembles of electrons-oscillators in the free space has been studied. It has been found that the guiding effects take place during propagation of wave beams along the electron beams that play the role of open active waveguides. In the linear stage of the interaction the quasisurface modes are generated, and in the nonlinear stage, the wave beam broadens and the electromagnetic energy is emitted into the outer space. There occurs stochastic retardation of particles interacting with the ensemble of electromagnetic waves which propagate at various angles to the system axis, and this can increase the efficiency of the system as compared to the closed waveguides. The effects of superradiance have been found in the bunches of electrons-oscillators that form moving active resonators. The development of thresholdless instabilities leads to bunching of electrons and their coherent emission. This emission is quasimonochromatic in the intrinsic frame of reference and a multifrequency one in the laboratory frame. If the translational velocity of a bunch is close to the velocity of light, then the radiant power is concentrated predominantly in the short-wave component.
Show AbstractPhysics of two-beam free-electron lasers
Physics of two-beam free-electron lasers
V.V. Kulish
The paper is concerned with the physical background of the operation of two-beam free-electron lasers (FELs). Both quasilinear and quadratic mechanisms of the superheterodyne amplification of electromagnetic waves are considered. It is asserted that, at the low- and medium-power levels, two-beam FELs will become the main amplifying devices in commercial systems operating in the submillimeter and IR wavelength ranges.
Show AbstractNumerical modeling of beams of charged particles
Numerical modeling of beams of charged particles
A.S. Roshal'
A survey is given of the state-of-the-art in numerical modeling of beams of charged particles propagating in electrodynamic systems and media. The features of various mathematical models of charged beams are described, the numerical methods of investigation are characterized, and the prospects for their development are discussed.
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