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1
Content available Symmetry of polychromatic beams and transverse energy flows
Mokhun Ihor I., Galushko Yurii K., Felde Christina V., Karabchiyvskiy Maksym D., Viktorovskaya Yuliia, Val Oleksandr D.
Opto-Electronics Review
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2024
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Vol. 32, No. 2
art. no. e150187
EN
The article considers the mechanisms of the formation of transverse energy flows in polychromatic fields with different structures. It is shown that the magnitude of the Poynting vector transverse component and the angular momentum for symmetric polychromatic beams are the same as in coherent monochromatic fields. Changes in the characteristics of energy flows due to the transformation and destruction of beam symmetry are demonstrated. The data of computer simulation are presented.
2
Content available New Surface-Plasmon-Polariton-Like Acoustic Surface Waves at the Interface Between Two Semi-Infinite Media
Kiełczyński Piotr
Archives of Acoustics
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2022
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Vol. 47, No. 3
363--371
EN
This paper presents theory of new shear horizontal (SH) acoustic surface waves that propagate along the interface of two semi-infinite elastic half-spaces, one of which is a conventional elastic medium and a second one an elastic metamaterial with a negative and frequency dependent shear elastic compliance. This new surface waves have only one transverse component of mechanical displacement, which has a maximum at the interface and decays exponentially with distance from the interface. Similar features are also shown by the acoustic shear horizontal Maerfeld-Tournois surface waves propagating at the interface of two semi-infinite elastic media due to the piezoelectric effect that should occur in at least one semi-space. The proposed new shear horizontal acoustic surface waves exhibit also strong formal similarities with the electromagnetic surface waves of the surface plasmon polariton (SPP) type, propagating along a metal-dielectric planar interface. In fact, the new shear horizontal elastic surface waves possess a large number of properties that are inherent for the SPP electromagnetic surface waves, such as strong subwavelength concentration of the wave field in the proximity of the guiding interface, low phase and group velocity etc. As a result, the new shear horizontal acoustic surface waves can find applications in sensors with extremely high sensitivity, employed in measurements of various physical parameters, such as viscosity of liquids, as well as in biosensors, chemosensors, or a near field acoustic microscopy (subwavelength imaging) and miniaturized devices of microwave acoustics.
3
Content available remote Wektor Poyntinga w analizie oscylacji mocy biernej w sieciach energetycznych
Dębicki P. S.
Zeszyty Naukowe Akademii Morskiej w Gdyni
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2016
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nr 95
15--33
PL
Niniejsza publikacja przeznaczona jest dla elektryków zainteresowanych, dyskutowanym ostatnio, zagadnieniem oscylacji mocy biernej w sieciach energetycznych. Niektóre z prac sugerują konieczność użycia wektora Poyntinga do analizy zjawiska. W tym artykule przeprowadza się Czytelnika w sposób przystępny poprzez wybrane podstawy teorii pola elektromagnetycznego, aby pokazać, dlaczego do analizy mocy, przesyłanej na częstotliwości 50 Hz wzdłuż jednorodnego wieloprzewodowego toru transmisyjnego, stosowanie wektora Poyntinga jest zbędne, natomiast przydatne do określania przestrzennego rozkładu gęstości mocy przenoszonej pomiędzy przewodami. Artykuł nie analizuje wpływu źródeł i obciążeń. Ich wpływ można uwzględnić poprzez superpozycję rozwiązań tu uzyskanych [9].
EN
The paper is addressed to the electrical engineers who are interested in a non-active power analysis in power lines. The Poynting vector application, as a necessary tool to explain physical phenomenon, has been suggested in some papers. The reader is guided through the chosen problems of the electromagnetic theory in an accessible way, in order to explain to him why in the analysis of 50 Hz power, which is transmitted along uniform multi-wire line, the application of the Poynting vector is unnecessary. Nevertheless, the Poynting vector could be useful in the analysis of the 3D density distribution of the power transferred between wires of the line. The influence of the sources and loadings is not analysed in this paper. It could be taken into account by creating a superposition of solutions obtained in this paper, which is discussed in an accompanying paper [9].
4
Content available remote Seismic Reverse Time Migration Using A New Wave-Field Extrapolator and a New Imaging Condition
Moradpouri F., Moradzadeh A., Pestana R. C., Monfared M.
Acta Geophysica
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2016
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Vol. 64, no. 5
1673--1690
EN
Prestack reverse time migration (RTM), as a two way wave-field extrapolation method, can image steeply dipping structures without any dip limitation at the expense of potential increase in imaging artifacts. In this paper, an efficient symplectic scheme, called Leapfrog-Rapid Expansion Method (L-REM), is first introduced to extrapolate the wavefield and its derivative in the same time step with high accuracy and free numerical dispersion using a Ricker wavelet of a maximum frequency of 25 Hz. Afterwards, in order to suppress the artifacts as a characteristic of RTM, a new imaging condition based on Poynting vector and a type of weighting function is presented. The capability of the proposed new imaging condition is then tested on synthetic data. The obtained results indicate that the proposed imaging condition is able to suppress the RTM artifacts effectively. They also show the ability of the proposed approach for improving the amplitude and compensate for illumination.
5
Content available The use of motion peculiarities of particles of the Rayleigh light scattering mechanism for defining the coherence properties of optical fields
Zenkova C, Soltys I, Angelsky P
Optica Applicata
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2013
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Vol. 43, nr 2
s. 297--312
EN
The paper proposes an alternative possibility for using the motion dynamics of tested particles of the Rayleigh light-scattering mechanism for estimating the degree of coherence of mutually orthogonal fields. The velocity of nanoparticles motion in the inhomogeneous optical field is chosen as the measuring parameter for diagnostics. The direct connection between the velocity of nanoscale particle motion and the degree of coherence of interacting fields is analytically demonstrated.
6
Content available remote Influence of the Brownian movement on the motion of nanoand micro-particles in the inhomogeneous optical field
Zenkova C. Y., Gorsky M. P., Soltys I. V., Angelsky P. O.
Opto-Electronics Review
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2012
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Vol. 20, No. 3
247-254
EN
The motion of light scattering particles of the Mie and Rayleigh micro- and nano-range type in the inhomogeneously-polarized optical field, with allowance made for the Brownian movement, is analysed in the paper. The spatial modulation of polarization in the observation plane determines the spatial modulation of the volume energy density. That is why the velocity and the resulting optical force, which cause the motion of the testing particles, change according to the degree of coherence of the interacting fields. The influence of the forces which arise in the viscous medium and cause the Brownian movement upon the mechanisms of manipulating and trapping testing particles by the optical field is studied.
7
Content available remote Reduction of eddy current losses by 2D-segmentation
Klocke M.
Przegląd Elektrotechniczny
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2007
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R. 83, nr 11
21-24
EN
The paper discusses the influence of a combined longitudinal and transversal segmentation of magnetic cores on eddy current losses based on an analytical solution of the underlying partial differential equation in the time-harmonic regime. Such a segmentation is often used for permanent magnets in brushless synchronous machines in order to reduce losses generated by field harmonics of higher frequency. The basic problem is analysed under simplifying assumptions, i.e. 1D-orientation of the magnetic field with no variation of the field strength in field direction.
PL
W pracy rozważono wpływ kombinowanej wzdłużnej i poprzecznej segmentacji rdzeni magnetycznych na straty wiroprądowe, wykorzystując rozwiązanie analityczne odpowiedniego równania różniczkowego cząstkowego przy wymuszeniu harmonicznym. Takie segmentacje są często stosowane w magnesach stałych bezszczotkowych maszyn synchronicznych w celu redukcji strat generowanych przez pola harmoniczne wyższej częstotliwości. Problem jest analizowany przy upraszczającym założeniu jednowymiarowej orientacji pola magnetycznego.
8
Content available remote The behavior of the Poynting vector in the area of elementary polarization singularities.
Mokhun I., Khrobatin R., Mokhun A., Viktorovskaya J.
Optica Applicata
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2007
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Vol. 37, nr 3
261-277
EN
The behavior of the Poynting vector in the area of elementary polarization singularities withone or two C-points, which are bounded by regular shape s-contour is considered. It has been shown that C-points are associated with the "vortex" kind singularities of the averaged transversal component of the Poynting vector if the handedness factor and topological charge of C-point are characterized by different signs. "Passive" Poynting singularities arise in the area if the signs are the same. It has been shown that the positions of the Poynting singularities shift relatively to the C-points under the phase and amplitude asymmetry of orthogonal components of the resulting field. The results of the computer simulation are presented.
9
Content available A Poynting Vector Approach to the Study of Power Flow through a Transformer
Todeschini G., Emanuel A. E.
Electrical Power Quality and Utilisation. Journal
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2007
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Vol. 13, nr 1
129-137
EN
This work deals with the flow of the electromagnetic energy through an idealized single-phase transformer supplied with nonsinusoidal voltage and supplying a nonlinear load. The electromagnetic flux components of the energy that flows from primary to secondary as well as the flux of energy stored in and ejected from the dielectric space surrounding the windings are identified and quantified. The electromagnetic flux components are correlated to well known instantaneous powers. These powers are not clever mathematic expedients but correct expressions that mirror the actual physical phenomena and lead to a more realistic interpretation of apparent power and its resolution.
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