Non-linear dielectrics (original) (raw)
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A Novel Theory on Effects of Alternative Potential in Dielectric Polarization
2014
6 Abstract: This paper presents a novel theory on the electronic polarization. The intention is that whenever an alternating potential occurs, a region is developed around it. This phenomenon can be named as Electro Tele Field (ETF). The dipoles are rotated due to the application of alternative voltage. The alternative voltage consists of positive and negative half cycles. During the positive half cycle, dielectric medium is positively polarized, and during the negative half cycle, the medium becomes as a negatively polarized. Hence dipoles get rotated. A continuity tester is able to detect that field. ETF can flow in conductors and penetrate in insulators. This paper explains the effect of alternative voltage on a dielectric. The main application is that the emf can be induced from one coil to another coil without current flow and electromagnetic field.
A New Approach in the Theory of Spatially-Restricted Nonlocal Dielectric Media
Russian Journal of Electrochemistry, 2018
A new method for the calculation of electric field distributions in the systems with spatiallyrestricted regions filled with polar media with nonlocal dielectric characteristics is proposed. The presence of regions with different dielectric properties in the system (as exemplified by the presence of an ion-filled cavity in which there is no polar medium surrounding the ion) is automatically taken into account within this procedure. The field distribution inside a uniform and isotropic nonlocal dielectric medium outside the spherical cavity containing a spherically symmetric charge distribution (the system represents the ion inside the polar solvent) has illustrated this new approach. In contrast to the previously suggested approach (dielectric approximation), where calculations of this characteristic required complex numerical and analytical calculations, the new method requires only single integration in order to determine the distribution of the potential of the electric field inside the polar medium with an arbitrary law of spatial dispersion of its dielectric permittivity (which can be specified eithter analytically or numerically).
Physical Review A
We present an operative approach to the macroscopic electromagnetic response of a finite size dispersive dielectric object in unbounded space, in the framework of quantum electrodynamics using the Heisenberg picture. The matter and the electromagnetic field are kept distinct and the polarization density field operator is expanded in terms of the static longitudinal and transverse modes of the object. These modes are a basis for the solenoidal vector fields defined on the region occupied by the object. To account for the dispersion and dissipation of the matter, the polarization is described through a Hopfield-type model. We apply the Coulomb gauge, we express the Coulomb electric field in terms of the polarization field, and we expand the transverse electromagnetic field in terms of the transverse plane wave modes of free space. We obtain the Heisenberg equations for the coordinate operators of the polarization in a closed form. They are coupled due to the interaction of the polarization with the radiation, through the transverse dyadic Green function for the vector potential in free space. The static longitudinal modes diagonalize the Coulomb interaction energy and the static transverse modes diagonalize the Ampere interaction energy. The other interaction energy terms between the modes are not diagonalized. Few static longitudinal and transverse modes are needed for dielectric objects with sizes of the order up to min ω {c0/[ω |χ(ω)|]} where χ(ω) is the susceptibility of the dielectric. We express the coordinate operators of the polarization as function of the free electric field operator and the free polarization field operator through the transfer matrix in the Laplace domain and the impulse response matrix in the time domain of the corresponding classical problem. The electric field operator has two contributions: the free electric field operator and the induced electric field operator, which is expressed as function of the polarization density field operator by means of the dyadic Green function in free space. Eventually, we apply the proposed approach to a disk with rounded edges for different dielectric susceptibilities.
The Lorentz local field in nonlinear dielectrics
Physica A: Statistical Mechanics and its Applications, 1997
An expression of the Clausius-Mossotti type is derived for the macroscopic electric polarization in a medium of nonlinear polarizable point dipoles, following the method proposed by Lorentz. The polarizing mechanism is assumed to have arbitrary nonlinear character, and no assumption on the strength of the electric field is made, As an application, a medium of two-level atoms, submitted to a harmonic electric field, is considered. For this case, the magnitude of the local field effects is investigated by comparison of the dipole moment per atom as calculated from the Clausius-Mossotti-type expression for a dense medium with that of an isolated atom.
Dielectric behavior of anisotropic inhomogeneities: interior and exterior point Eshelby tensors
Journal of Physics A: Mathematical and Theoretical, 2008
In this work we analyze the problem of finding the electric behavior of an anisotropic ellipsoid (arbitrarily shaped) placed in a dielectric anisotropic environment. We suppose that the whole system is exposed to a uniform electric field remotely applied. In order to find the resulting electric quantities inside the particle and outside it we adopt a technique largely utilized for solving similar problems in elasticity theory. The inhomogeneity problems in elastostatics are solved within the framework of the Eshelby theory, which adopts, as crucial points, the concepts of eigenstrains and inclusions. The generalization and assessment of such an approach for the dielectric inhomogeneity problems is here addressed by means of the introduction of the concepts of eigenfields and inclusions in electrostatics. The advantages of this methodology are mainly two: firstly, we can consider completely arbitrary dielectric anisotropic behavior both for the particle and the host matrix. Secondly, we easily find explicit expressions for the electric quantities both inside and outside the inhomogeneity. The problem under consideration was solved in earlier literature by analyzing the singularity of the dyadic Green function, expressed as a two-dimensional integral. Here we propose a reformulation described by a one-dimensional integral obtained from explicitly electrostatic analysis, which can have both pedagogical and computational importance. We also introduce a method to generalize these results to the case of an arbitrary nonlinear anisotropic ellipsoid embedded in a linear anisotropic matrix. Finally, we show some applications to the dielectric characterization of anisotropic composite materials.
Polarizability of dielectric prolate half ellipse
2021 15th European Conference on Antennas and Propagation (EuCAP), 2021
This article presents a method for solving the polarizability of a dielectric prolate half ellipse as a function of its relative electric permittivity. The considered geometry consists of two conjoined half ellipses with different permittivities. The polarizability depends on the excitation field direction, therefore can be presented in the form of dyadic consisting of two components that are series and parallel polarizabilities. The method is based on analytical series expansions with coefficients obtained as a numerical solution of a matrix equation.
Images in linearly conducting dielectrics
IEE Proceedings - Science, Measurement and Technology, 1997
Methods of images for electrostatic fields and steady conduction fields are fairly well known. Whenever applicable, they have made the solution of field problems much simpler. However, when dealing with lossy dielectrics both permittivity and nonzero conductivity are to be considered. A generalised method of images is developed which can deal with such linearly lossy (conducting) dielectrics. For linearly conducting dielectrics, a point charge is equivalent to a point current source and vice versa. At t = 0+, only the dielectric image will be seen. Subsequently, because of the finite nonzero conductivities of the associated media, a current will flow and surface charges will accumulate at the interface due to the mismatch in the material properties. The equattion governing this surface-charge accumulatioin is derived. Linearity of the media permits fields in either medium to be obtained by superposing the fields due to the dielectric images and that due to the interfacial charges. The field can be obtained in either medium by replacing these surface charges by an equivalent point charge kept ait the appropriate image point. This equivalent point charge satisfies a similar differential equation in time to that of the surface charge. The cases of time-varying chargeicurrent sources and the source-current requirement for keeping any point very close to the source at a specified potential are also discussed.
The Theory of Electrodynamics in a Linear Dielectric
We adopt the continuum limit of a linear, isotropic, homogeneous, transparent, dispersionnegligible dielectric of refractive index n and examine the consequences of the effective speed of light in a stationary dielectric, c/n, for D'Alembert's principle and the Lagrange equations. The principles of dynamics in the dielectric-filled space are then applied to the electromagnetic Lagrangian and we derive equations of motion for the macroscopic fields. A direct derivation of the total energymomentum tensor from the field strength tensor for the electromagnetic field in a dielectric is used to demonstrate the utility of the new theory by resolving the century-old Abraham-Minkowski electromagnetic momentum controversy in a way that preserves the principles of conservation of energy, conservation of linear momentum, and conservation of angular momentum.
Diatomic elastic dielectrics with polarization inertia
International Journal of Engineering Science, 1989
41 this work, utilizing a variational formulation developed by the present authors [fat. J. Engng Sci. 26,86%X71 (1988)], we have obtained the field equations and the constitutive relations of an elastic diatomic dielectric with polarization inertia effects. The balance equations and the constitutive relations are linearized and the propagation of time harmonic waves in such a medium is studied. The result shows that there are 12 waves which can propagate in such a structured medium. Of these 12 waves, four are longitudinal and the remaining eight waves are transverse. Furthermore, of these 12 waves, three of them are of acoustical type and the others are of optical character. It has been also observed that all the waves are dispersive.
Polarization-based calculation of the dielectric tensor of polar crystals
Physical review letters, 1997
We present a novel method for the calculation of the static and electronic dielectric tensor of polar insulating crystals based on concepts from the modern theory of dielectric polarization. As an application, we present the first ab initio calculation of the dielectric constants in the wurtzite III-V nitrides AlN, GaN, and InN.