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Vol 71, No 3 (2016)

Nuclear and Particle Physics (Review)

Electromagnetic processes in silver isotopes

Ishkhanov B.S., Kuznetsov A.A., Lanskoy D.E., Martynov A.A.

Abstract

Peculiarities of electromagnetic interactions in silver isotopes are considered. Excited states of Ag isotopes are studied as a function of the mass number A = 95–117. Low-lying excited states reveal clear features that are specific for rotational spectra for the energies E < 4–5 MeV. In the energy domain above the nucleon separation threshold of 5–10 MeV, single-particle excited states overlap and produce a continuous spectrum. For energies E = 10–35 MeV, excitation of giant dipole resonance plays the most important role in Ag isotopes. Experimental data on the cross sections of photonuclear reactions in Ag isotopes are analyzed.

Moscow University Physics Bulletin. 2016;71(3):215-228
pages 215-228 views

Theoretical and Mathematical Physics

Nonlinear ion acoustic solitary waves in electron-positron-ion inhomogeneous plasma

Mowafy A.E.

Abstract

A theoretical investigation has been made for studying the propagation of ion-acoustic waves (IAWs) in a weakly inhomogeneous, collisionless, unmagnetized, three-component plasmas, whose constituents are inertial ions, nonthermal electrons, and Boltzmannian positrons. Employing reductive perturbation method (RPM), the variable coefficients Korteweg-de Varies equation (KdV) is derived. At the critical ion density, the KdV equation is not suitable for describing the system. Thus, a new set of stretched coordinates is considered to derive the modified variable coefficients KdV equation. Above (below) this critical point the system supports compressive (rarefactive) solitons. The effect of plasma parameters on the soliton profile has been considered. It has been shown that the width and the amplitude of the soliton affected by wave propagation speed, ratio of positron-to-electron density, and nonthermal parameter.

Moscow University Physics Bulletin. 2016;71(3):229-236
pages 229-236 views

The operational solution of fractional-order differential equations, as well as Black–Scholes and heat-conduction equations

Zhukovsky K.V.

Abstract

Operational solutions to fractional-order ordinary differential equations and to partial differential equations of the Black–Scholes and of Fourier heat conduction type are presented. Inverse differential operators, integral transforms, and generalized forms of Hermite and Laguerre polynomials with several variables and indices are used for their solution. Examples of the solution of ordinary differential equations and extended forms of the Fourier, Schrödinger, Black–Scholes, etc. type partial differential equations using the operational method are given. Equations that contain the Laguerre derivative are considered. The application of the operational method for the solution of a number of physical problems connected with charge dynamics in the framework of quantum mechanics and heat propagation is demonstrated.

Moscow University Physics Bulletin. 2016;71(3):237-244
pages 237-244 views

Nuclear and Particle Physics

A high-intensity electron-beam source

Vladimirov I.Y., Ishkhanov B.S., Ovchinnikova L.Y., Shvedunov V.I., Yurov D.S.

Abstract

A description is given and calculation results are presented for a high-intensity electron-beam source that can produce sequences of four electron bunches of 1 nC each, following at a frequency of 50 Hz. The root-mean-square normalized transverse beam emittance of the bunch does not exceed 4 mm mrad, the root-mean-square duration is 3 ps, and the energy can be adjusted in the 35–50 MeV range.

Moscow University Physics Bulletin. 2016;71(3):245-252
pages 245-252 views

Optics and Spectroscopy. Laser Physics

The state vector of a quantum system: Mathematical fiction or physical reality?

Belinsky A.V., Zhukovskiy A.K.

Abstract

A version of an experiment with a correlated pair of entangled particles is considered. This experiment demonstrates an interesting effect of variations in the entangled photon polarization that shows the reality of all of the various superposition components and the corresponding state vector of the quantum system. The possible consequences of this are analyzed.

Moscow University Physics Bulletin. 2016;71(3):253-257
pages 253-257 views

Specific features of interference of photons and other quantum particles

Belinsky A.V., Lapshin V.B.

Abstract

Specific features of the behavior of quantum particles in different experimental situations are considered. The variants of two-beam interference of single photon and other quantum particles, as well as their ability to form “standing” and “progressive” waves with the interference minima, i.e., “dead” zones in the propagation path, are studied. We also consider some type of quantum particle teleportation in an unconventional understanding of this word, where elementary particles overcome regions of the space where they cannot be, or rather the borders where the probability of finding them is zero. At these boundaries there is no pulse impact of particles on anything, it is as if they are unobservable. When observing three-beam interference, it turns out that all three modes should be present simultaneously in the light field prior to photodetection. If each mode involves a photon, it contradicts the energy conservation law, it is indicative of the fact that the observed quantity (number of photons in the field) has no any particular value prior to the measurement (a priori) unless the quantum system is in the eigen state of a measured value (Fock state).

Moscow University Physics Bulletin. 2016;71(3):258-265
pages 258-265 views

Phase patterns in a nonlinear ring resonator

Ivanov V.Y., Ivanova (Polyakova) I.B.

Abstract

The processes of the formation of phase spatial structures (patterns) in the cross section of a light wave in a passive nonlinear ring resonator are considered. Analytical and numerical calculations are performed. The potential to form roll- and hexagon-type phase patterns, which are the product of competitive dynamics of nonlinear modes in a resonator, and more complex phase patterns associated with cooperative dynamics of nonlinear modes is demonstrated by numerical modeling.

Moscow University Physics Bulletin. 2016;71(3):266-271
pages 266-271 views

Condensed Matter Physics

First-principles study of the structural, elastic, mechanical, electronic, and optical properties of cubic Mg2TiO4

Zeng W., Liu Q., Liu Z.

Abstract

We have performed ab-initio total energy calculations using the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory (DFT) to study structural, elastic, mechanical, electronic, and optical properties of cubic Mg2TiO4. The calculated lattice parameter a is in good agreement with the experimental values. The independent elastic constants are calculated. The mechanical properties including bulk, shear and Young’s modulus, Poisson’s coefficient, compressibility and Lamé’s constants are obtained using the Voigt-Reuss-Hill method. Debye temperature is estimated using the Debye-Grüneisen model. Band structure, density of states and charge densities are shown and analyzed. In order to clarify the mechanism of optical transitions of cubic Mg2TiO4, the complex dielectric function, refractive index, extinction coefficient, reflectivity, absorption coefficient, loss function and complex conductivity function are calculated.

Moscow University Physics Bulletin. 2016;71(3):272-278
pages 272-278 views

Chemical Physics, Physical Kinetics, and Plasma Physics

Survey of segregation alteration of hydrogen-helium mixtures via structure factor

Motevalli S.M., Yaraei M., Azimi M.

Abstract

In this study, thermodynamic instabilities in hydrogen-helium fluid mixture have been analyzed. These kinds of investigations are inevitable for indicating hydrodynamic transitions in Hydrogen-Helium fluid mixture. Therefore, first we have derived equation of state of mixture via Barker-Henderson statistical perturbation theory. Moreover, we have used Yiping radial distribution function in calculating perturbed terms. Via equation of state, we have calculated excess Gibbs free energy and the Gibbs free energy in the long wavelength limit. By means of this energy in hand we could estimate degree of hetero-coordination and segregations of this mixture which is a measure for defining thermodynamic instabilities. At last, these measurements have made us capable of anticipating thermodynamic instabilities and coordination of mixture in different concentrations.

Moscow University Physics Bulletin. 2016;71(3):279-283
pages 279-283 views

Rogue waves for Kadomstev-Petviashvili solutions in a warm dusty plasma with opposite polarity

El-Shewy E.K., Abdelwahed H.G., Abdo N.F., Shahein R.A.

Abstract

Kadomstev-Petviashvili (KP) equation is derived using reductive perturbation method. This equation transformed into a nonlinear Schrödinger equation (NLS) by using appropriate variable transformations. When the carrier wave frequency is much smaller than the dust plasma frequency, the DA waves generating modulated wave packets in the form of rogue waves. The dependence of rogue wave profile on system plasma parameters investigated numerically. The parameters in this model are within the ranges corresponding to upper mesosphere, cometary tails and Jupiter’s magnetosphere.

Moscow University Physics Bulletin. 2016;71(3):284-291
pages 284-291 views

Astronomy, Astrophysics, and Cosmology

Magnetospheric dynamics during the storm of February 14, 2009

Kalegaev V.V., Nazarkov I.S.

Abstract

The structure of the magnetic field in the magnetospheric during the storm of February 14, 2009 is studied. The model parameters that characterize the magnetospheric magnetic field are calculated every hour on the basis of solar wind data and the evolution of the magnetic field during the storm is reproduced using the A2000 model of the Earth’s magnetosphere. It is shown that extremely quiet geomagnetic conditions in 2009 promoted the expansion of the magnetosphere and were favorable for the formation of magnetic-island-like structures (plasmoids) in the geomagnetic tail. It is ascertained that negative variations in the Bz component could occur in the nightside magnetosphere in situations where the magnetic flux through the tail lobes exceeded certain thresholds, which depend on the parameters of the magnetospheric current systems. It is shown that the formation of magnetic islands decreases the magnetic flux through the tail lobes and prevents excessively strong development of the magnetic field in the tail.

Moscow University Physics Bulletin. 2016;71(3):292-298
pages 292-298 views

Improvement of the orbit of the Spektr-R spacecraft in the RadioAstron mission on the basis of radio range and Doppler measurements

Zhamkov A.S., Zharov V.E.

Abstract

The first results of the improvement of the state vector of the Spektr-R spacecraft of the RadioAstron mission, which is a part of an earth–space radio interferometer, are presented. The state vector includes three components for the spacecraft position and three components for its velocity in the Geocentric Celestial Reference System. Kalman filtering on the basis of radio range and Doppler data allows refinement of the components at each iteration. It is shown that orbit improvement increases the accuracy of the orbit determined at the Keldysh Institute of Applied Mathematics.

Moscow University Physics Bulletin. 2016;71(3):299-308
pages 299-308 views

A multipole analysis of the apparent motion of reference radio sources

Sazhin M.V., Sazhina O.S., Sementsov V.N., Siversky M.N., Zharov V.E., Kuimov K.V.

Abstract

In this paper, the apparent motions of quasars, which are the reference sources of the international celestial reference system (ICRS), are analyzed. Kinematic parameters from four catalogs compiled by different research groups are used. Apparent motions are expanded on a special set of vector functions on the sphere that are an irreducible representation of the rotation group O(3). The degree of the noninertiality of the barycentric reference system caused by the rotation of the solar system around the galactic center is estimated according to expansion coefficients. The direction and magnitude of the acceleration vector are calculated and compared with the alternative estimates. This method is discussed as a way to test Newton’s law on a large scale.

Moscow University Physics Bulletin. 2016;71(3):309-316
pages 309-316 views

A satellite cluster as a gravitational-wave detector

Sazhin M.V., Li Y.

Abstract

The detection of gravitational waves by a cluster of satellites is considered. The detector is an optical interferometer formed of several satellites. The calculations for three spacecraft are given. The complete detector response to the monochromatic gravitational wave generated by a binary star is computed.

Moscow University Physics Bulletin. 2016;71(3):317-322
pages 317-322 views

Physics of Earth, Atmosphere, and Hydrosphere

The run-up of nonlinearly deformed sea waves on the coast of a bay with a parabolic cross-section

Didenkulov O.I., Didenkulova I.I., Pelinovsky E.N.

Abstract

The run-up of long waves on the coast of a bay with a parabolic cross-section, where the region of constant depth along the principal axis of the bay is connected with the linearly inclined segment, is considered. The study is carried out analytically in the framework of the nonlinear shallow-water theory under the approximation that the height of the initial wave is small compared to the basin depth, and the reflection from the inflection point of the bottom is negligibly small. Three types of incident waves, viz., a sinusoidal wave and solitary waves of positive and negative polarities, are considered in detail. It is shown that a sinusoidal wave undergoes nonlinear deformation at a segment of constant depth faster than solitary waves of positive and negative polarities. Solitary waves of negative polarity steepen somewhat faster than solitary waves of positive polarity. Waves of positive polarity steepen at wave front, while waves of negative polarity steepen at wave rear. These differences in steepness may become crucial at the wave run-up stage, since the wave run-up height on the coast of a bay with a parabolic cross-section is directly proportional to the steepness of a wave that arrives at the slope and can lead to the anomalous run-up of waves on the coast.

Moscow University Physics Bulletin. 2016;71(3):323-328
pages 323-328 views

Modeling the problem of low-orbital satellite UV-tomography of the ionosphere

Nesterov I.A., Padokhin A.M., Andreeva E.S., Kalashnikova S.A.

Abstract

The results of modeling the direct and inverse problems of low-orbital satellite ultraviolet (UV) tomography of the ionospheric 135.6 OI volume emission rate are presented. The direct problem was solved with the orbital geometry of DMSP block 5D3 satellites with SSUSI and SSULI UV spectrographs among the other payloads, the real operating parameters of these instruments (the scan rate and the interval of scan angles), and the set of the model distributions of the volume emission rate that contain irregularities on various scales. The solution of the direct problem yields the radiation intensities in the 135.6 nm line, which is used as the input data for reconstructing the initial (prototype) model distributions of the volume emission rates. The obtained system of linear equations (SLE) was solved using the Algebraic Reconstruction Technique (ART) and Simultaneous Iterative Reconstructive Technique (SIRT) algorithms, which are highly efficient in problems of the low-orbit radio tomography of the ionosphere. It is shown that the initial model distribution can be successively reconstructed if one takes the non-negativity condition of the solution into account, uses weighting functions to decrease the solution in the regions where it is known to be a priori small, and applies inter-iteration smoothing to eliminate the effects of the approximation errors. Here, the averaging parameters should decrease in the course of the iterations. With these constraints fulfilled, the computational costs of the ART- and SIRT-based solutions are similar, while the reconstruction error is approximately 6%. The influence of random errors and bias in the data on the results of the reconstruction is explored. It is shown that with a given error level of the initial data the parameters of the reconstruction algorithms can be adjusted in such a way as to efficiently suppress the influence of the noise with a relative amplitude of 2–3% on the solution.

Moscow University Physics Bulletin. 2016;71(3):329-338
pages 329-338 views

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