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Showing papers on "Scalar potential published in 1994"


Journal ArticleDOI
Vernon Cooray1
TL;DR: In this paper, a comparison between two coupling models, the Rusck model and the wave antenna model, for estimating the lightning-induced overvoltages in power lines is made.
Abstract: A comparison is made between two coupling models frequently used to estimate the lightning-induced overvoltages in power lines. The first model was introduced by Rusck (1957) and the second model by Agrawal, Price, and Gurbaxani (1980). In the nomenclature adopted in this paper, the first model is referred to as the "Rusck model" and the second as the "Wave Antenna Model." The transmission line equations of the Rusck model can be written in such away that the forcing term in the equations is the horizontal electric field. The results show that the Rusck model is incomplete. It takes into account the portion of the horizontal electric field generated by the gradient of the scalar potential but neglects the contribution from the vector potential. This defect in the Rusck model makes it source-dependent. That is, the Rusck model can give accurate results only when the spatial location of the source that generates the electromagnetic field is such that the contribution of the vector potential to the horizontal field is either zero or can be neglected. Under such circumstances the Rusck model and the Wave Antenna Model are described by the same transmission line equations, and the results predicted by the two models are identical. >

85 citations


Journal ArticleDOI
TL;DR: In this article, the relativistic transport model is extended to include the kaon degree of freedom, and the authors find that the attractive kaon scalar mean-field potential in the dense matter leads to an enhanced kaon yield in heavy-ion collisions at energies of about 1 GeV/nucleon that are below the threshold for kaon production from the nucleon nucleon interaction in free space.

64 citations


Journal ArticleDOI
TL;DR: In this article, the joint scalar, scalar gradient probability density function (PDF) of an inert non-premixed scalar diffusing in a one-dimensional system of random-sized lamellas is investigated by numerical simulation.
Abstract: The joint scalar, scalar gradient probability density function (PDF) of an inert nonpremixed scalar diffusing in a one‐dimensional system of random‐sized lamellas is investigated by numerical simulation. The form of the scalar PDF, at a given RMS value, is nearly identical to that predicted by direct numerical simulation (DNS) of scalar mixing in isotropic turbulence and the mapping closure, and the moments of both the scalar and the scalar gradient suggest that their limiting marginal PDF are Gaussian. The joint scalar, scalar gradient PDF is found to be restricted to a bounded region in the scalar–scalar gradient plane, whose form is independent of the initial mixing ratio. These results are incorporated into the Fokker–Planck (FP) model for the joint scalar, scalar gradient PDF, and the improved model shows good agreement with numerical simulation data. An extension of the FP model that includes random stretching of the scalar gradient in isotropic turbulence is formulated.

56 citations


Journal ArticleDOI
TL;DR: In this article, the authors compared different techniques based on the theory of images and the finite element method enabling to calculate the leakage field and the static electromagnetic forces on the windings of power transformers.
Abstract: The paper compares different techniques based on the theory of images and the finite element method enabling to calculate the leakage field and the static electromagnetic forces on the windings of power transformers. The models developed have been applied to the one phase part of a three phase shell type power transformer and the results are verified experimentally. Both cases, that of approximate two dimensional analysis and the three dimensional configuration, have been studied. A particular three dimensional finite element formulation involving only a scalar potential was found to be suitable for this class of problems. >

53 citations


Journal ArticleDOI
TL;DR: In this paper, the relativistic transport model is extended to include the kaon degree of freedom, and the propagation of kaons in the mean-field potential and the kon-baryon elastic scattering are explicitly treated.
Abstract: The relativistic transport model, in which the nucleon effective mass is connected to the scalar field while its energy is shifted by the vector potential, is extended to include the kaon degree of freedom. We further take into account the medium modification of the kaon mass due to the explicit chiral symmetry breaking. Both the propagation of kaons in the mean-field potential and the kaon-baryon elastic scattering are explicitly treated in our study. We find that the attractive kaon scalar mean-field potential in the dense matter leads to an enhanced kaon yield in heavy-ion collisions at energies of about 1 GeV/nucleon. The final-state kaon-baryon scattering is seen to affect significantly the kaon momentum spectra, leading to an enhanced yield of kaons with large momenta or at large laboratory angles. With a soft nuclear equation of state and including the attractive kaon scalar potential, the calculated kaon energy spectra agree with the data from the heavy-ion synchrotron at GSI.

50 citations


Journal ArticleDOI
TL;DR: In this article, the Bern-Kosower method was used to calculate the higher derivative expansion of the one-loop effective action for an external scalar potential in O(T**7) time.
Abstract: The higher derivative expansion of the one-loop effective action for an external scalar potential is calculated to order O(T**7), using the string-inspired Bern-Kosower method in the first quantized path integral formulation. Comparisons are made with standard heat kernel calculations and with the corresponding Feynman diagrammatic calculation in order to show the efficiency of the present method.

48 citations


Journal ArticleDOI
TL;DR: In this article, the T/sub 0/spl Omega/ formulation was used to model a 100 MVA power transformer short circuit test in the transient state and the same device was studied at no-load.
Abstract: Most of the electromagnetic devices work connected to an electric circuit and their numerical simulation in 3D leads to a large number of unknowns. To deal with these problems we propose to use the T/sub 0//spl Omega/ formulation and describe the way of coupling magnetic and electric circuit equations. The coupling is obtained by expressing the electric vector potential T/sub 0/ from the current and the flux of induction and from the magnetic scalar potential /spl Omega/. To consider the magnetic nonlinearity we use the Newton-Raphson procedure. This formulation is used to model a 100 MVA power transformer short circuit test in the transient state. The same device is studied at no-load. >

46 citations


Journal ArticleDOI
TL;DR: An SO(10) grand unified theory in the formulation of non-commutative geometry is constructed by extending the number of discrete points to six and adding a singlet fermion and a 16 s Higgs field.
Abstract: We construct an SO(10) grand unified theory in the formulation of non-commutative geometry. The geometry of space-time is that of a product of a continuos four dimensional manifold times a discrete set of points. The properties of the fermionic sector fix almost uniquely the Higgs structure. The simplest model corresponds to the case where the discrete set consists of three points and the Higgs fields are 16 s × 16 s and 16 s × 16 s . The requirement that the scalar potential for all the Higgs fields not vanish imposes strong restrictions on the vacuum expectation values of the Higgs fields and thus the fermion masses. We show that it is possible to remove these constraints by extending the number of discrete points to six and adding a singlet fermion and a 16 s Higgs field. Both models are studied in detail.

43 citations


Journal ArticleDOI
TL;DR: In this paper, a new application of the self-correcting procedure to computational liquid metal magnetohydrodynamics is described, where the conservation law of the electric current density incorporated in a Poisson equation for the scalar potential plays an important role of correcting this potential.

31 citations


Journal ArticleDOI
TL;DR: It is shown use of magnetostatic scalar potential can lead to a very unstable iterative process because of the shape of the residual function which is to be cancelled and Newton-Raphson method is much more efficient.
Abstract: Deals with convergence difficulties using Newton-Raphson method in nonlinear magnetostatic problems. It is shown use of magnetostatic scalar potential can lead to a very unstable iterative process because of the shape of the residual function which is to be cancelled. Such effects do not exist when the vector potential is used and Newton-Raphson method is much more efficient. A simple example points out the behavior of Newton-Raphson method for both formulations. A method for reducing the CPU time required for determining the relaxation factor used to insure convergence in the case of scalar potential is also presented. >

29 citations


Journal ArticleDOI
P.A. Kok1, D. De Zutter1
TL;DR: In this article, a quasi-static method is described for calculating the excess inductance of via's, and an integral equation based on the scalar magnetic potential /spl psi/ is solved.
Abstract: A quasi-static method is described for calculating the excess inductance of via's. The considered via geometry contains connecting strips, pads on the via, and a finite ground plane thickness. An integral equation based on the scalar magnetic potential /spl psi/ is solved. The inductance is found by calculating the magnetic flux through a cut introduced to define /spl psi/ in an unequivocal way. The problem is generally solved for via through-holes; the grounded via-configuration is found as a limiting case. The influence of the geometric parameters on the via inductance is examined. >

Journal ArticleDOI
TL;DR: In this article, the general scalar potential consistent with (p,q) supersymmetry in two-dimensional non-linear sigma-models with torsion was determined. But this result was not generalized to supersymmetric (2,2) and (4,4) models.
Abstract: We determine the general scalar potential consistent with (p,q) supersymmetry in two-dimensional non-linear sigma-models with torsion, generalizing previous results for special cases. We thereby find many new supersymmetric sigma-models with potentials, including new (2,2) and (4,4) models.

Journal ArticleDOI
TL;DR: In this article, a method of simulating both linear and nonlinear 3D magnetostatic field with open boundary is described based on the integration with total scalar potential on the surface or in the volume of magnetic materials.
Abstract: A method of simulating both linear and nonlinear 3D magnetostatic field with open boundary is described. It is based on the integration with total scalar potential on the surface (linear problems) or in the volume (nonlinear problems) of magnetic materials. For nonlinear problems, this procedure can avoid the cancellation errors and is convenient because of the use of total scalar potential and the volume integration only. It was tested by a given example and was applied to a deflection field calculation of multipole yoke. >

Journal ArticleDOI
TL;DR: In this article, acoustic phonon modes confined to a GaAs cylindrical quantum wire within AlAs are analytically investigated within the context of an elastic continuum model, where elastic properties are assumed to be isotropic for both materials.
Abstract: Acoustic phonon modes confined to a GaAs cylindrical quantum wire within AlAs are analytically investigated within the context of an elastic continuum model. Elastic properties are assumed to be isotropic for both materials for mathematical convenience. The displacement vector is expressed by the scalar potential and two vector potentials. The confined acoustic phonon modes are classified into three types according to the rotational symmetry of the potential functions: dilatational, torsional, and flexural modes. Dispersion curves of the modes show phonon subband structures with finite cutoff frequencies due to confinement of waves in lateral directions. The density of the confined phonon modes accordingly appears as staircaselike structures.

Journal ArticleDOI
TL;DR: In this paper, a 3D finite element (3D-FE) method for the computation of global distributions of 3D magnetic fields in electric machines containing permanent magnets is presented.
Abstract: A three dimensional finite element (3D-FE) method for the computation of global distributions of 3D magnetic fields in electric machines containing permanent magnets is presented. The formulation of this 3D-FE method including 3D permanent magnet modeling, which is based on a coupled magnetic vector potential-magnetic scalar potential (CMVP-MSP) approach, is given. The development of the necessary 3D-FE grids and algorithms for the application of the method to an example brushless DC motor, whose field is three dimensional due to the skewed permanent magnet mounts on its rotor, is also given here. A complete set of results of application of the method to the computation of the global 3D field distributions and associated motor parameters under no-load and load conditions are detailed in a companion paper. >

Journal ArticleDOI
TL;DR: In this article, the Bern-Kosower method was used to calculate the higher derivative expansion of the one-loop effective action for an external scalar potential, using the string-inspired Bern-inspired Kosower method.
Abstract: The higher derivative expansion of the one-loop effective action for an external scalar potential is calculated to order {ie111-1}, using the string-inspired Bern-Kosower method in the first quantized path integral formulation Comparisons are made with standard heat kernel calculations and with the corresponding Feynman diagrammatic calculation in order to show the efficiency of the present method

Journal ArticleDOI
TL;DR: In this paper, a method for analytically representing the magnetic field due to the cross-tail current and its closure on the magnetopause is presented, which can also be used to confine the modeled field of any other interior magnetic source, though the model current must always flow in closed circuits.
Abstract: A method is presented for analytically representing the magnetic field due to the cross-tail current and its closure on the magnetopause. It is an extension of a method used by Tsyganenko (1989b) to confine the dipole field inside an ellipsoidal magnetopause using a scalar potential. Given a model of the cross-tail current, the implied net magnetic field is obtained by adding to the cross-tail current field a potential field B = - del gamma, which makes all field lines divide into two disjoint groups, separated by the magnetopause (i.e., the combined field is made to have zero normal component with the magnetopause). The magnetopause is assumed to be an ellipsoid of revolution (a prolate spheroid) as an approximation to observations (Sibeck et al., 1991). This assumption permits the potential gamma to be expressed in spheroidal coordinates, expanded in spheroidal harmonics and its terms evaluated by performing inversion integrals. Finally, the field outside the magnetopause is replaced by zero, resulting in a consistent current closure along the magnetopause. This procedure can also be used to confine the modeled field of any other interior magnetic source, though the model current must always flow in closed circuits. The method is demonstrated on the T87 cross-tail current, examples illustrate the effect of changing the size and shape of the prescribed magnetopause and a comparison is made to an independent numerical scheme based on the Biot-Savart equation.

Journal ArticleDOI
TL;DR: In this article, a space-domain mixed-potential integral equation approach is applied in conjunction with the method of moments to compute the radar cross-section (RCS) of coax-loaded micro-slrip patch antennas having arbitrary or irregular shapes.
Abstract: A space-domain mixed-potential integral equation approach is applied in conjunction with the method of moments to compute the radar cross-section (RCS) of coax-loaded microslrip patch antennas having arbitrary or irregular shapes. The effects of Lhe substrate—which may be electrically thick and may consist of any number of planar, possibly uniaxially anisotropic dielectric layers, backed by a ground plane—are rigorously incorporated in the analysis by means of the vector and scalar potential Green's functions. The latter are expressed in terms of the voltages and currents on transmission line analogs of the layered medium, associated with TM and TE partial fields. The current distribution on the microstrip patch is approximated using vector basis functions defined over triangular elements and the coax probe current is expanded in terms of piecewise-lincar subdomain basis functions. A simple probe-to-patch attachment mode, compatible with the triangular element model of the microstrip patch, is us...

Journal ArticleDOI
TL;DR: In this article, the transverse profile of the color flux tube in the context of the Schwinger's mechanism for particle production was studied by representing the transversal profile in terms of an effective transverse scalar potential, and the classical turning point for the potential is of the order of 0.6 fm.

Journal ArticleDOI
TL;DR: In this article, a 2D finite element procedure devised to handle both soft magnetic materials and hysteretic ones, on basis of Preisach's classical approach for scalar and vector hysteresis, is presented.
Abstract: In this paper a 2D Finite Element procedure devised to handle both soft magnetic materials and hysteretic ones, on basis of Preisach's classical approach for scalar and vector hysteresis, is presented. In the scalar case, a model identified by a reduced set of experimental data is proposed, whereas for the vector case a more demanding identification procedure is required. The resulting modular "Preisach engines" are used to solve some problems of practical engineering type. >

Journal ArticleDOI
TL;DR: In this paper, a thin sheet finite element crack model was developed to analyze the electromagnetic interaction between probe coils and crack-type defects in eddy current NDE (Nondestructive Evaluation).
Abstract: A thin sheet finite element crack model has been developed to analyze the electromagnetic interaction between probe coils and crack-type defects in eddy current NDE (Nondestructive Evaluation). The crack type irregularities are treated here as nonconducting thin sheets with negligible thickness to avoid the discretization along their width. On the crack surfaces magnetic vector potential with zero normal component and jumping electric scalar potential ensure the proper behavior of the electromagnetic field. The model can be incorporated into the finite element formulation without disrupting the primary finite element scheme. A benchmark problem has been solved, and numerical results of the crack model have been compared to experimental data. >

Journal ArticleDOI
TL;DR: In this paper, vector and scalar potential formulations are used together to facilitate accurate calculations of two-dimensional fields and forces in a synchronous motor, and numerical results confirm the accuracy of the ripple solution in the sliding surface model.
Abstract: Vector and scalar potential formulations are used together to facilitate accurate calculations of two-dimensional fields and forces in a synchronous motor. The scalar potential method employs a precomputed edge-based source field. The finite element model with a sliding surface in the air gap is implemented to obtain consistent results for the ripple force. Theoretical analysis presented in the paper and numerical results confirm the accuracy of the 'ripple solution' in the sliding surface model. >

Journal ArticleDOI
TL;DR: In this article, the authors investigated the conformal factor contribution to the effective potential of scalar fields and explored the possibility of the first order phase transition and the induced values of Newtonian and cosmological constants.
Abstract: Quantum theory of conformal factor coupled with matter fields is investigated. The more simple case of the purely classical scalar matter is considered. It is calculated the conformal factor contribution to the effective potential of scalar field. Then the possibility of the first order phase transition is explored and the induced values of Newtonian and cosmological constants are calculated.

Posted Content
TL;DR: In this paper, the one-loop effective action for the case of a massive scalar loop in the background of both a scalar potential and an abelian or non-abelian gauge field is written in a one-dimensional path integral representation.
Abstract: The one–loop effective action for the case of a massive scalar loop in the background of both a scalar potential and an abelian or non–abelian gauge field is written in a one–dimensional path integral representation. From this the inverse mass expansion is obtained by Wick contractions using a suitable Green function, which allows the computation of higher order coefficients. For the scalar case, explicit results are presented up to order O(T 8 ) in the proper time expansion. The relation to previous work is clarified.

Proceedings ArticleDOI
20 Jun 1994
TL;DR: In this paper, a mixedpotential integral equation (MPE) method was applied to the electromagnetic analysis of vertical and horizontal conducting structures in a multilayered environment, various Green's functions for the magnetic vector potentials and electric scalar potentials are required.
Abstract: In applying mixed-potential integral equation methods to the electromagnetic analysis of vertical and horizontal conducting structures in a multilayered environment, various Green's functions for the magnetic vector potentials and electric scalar potentials are required. With the Cartesian coordinates defined the present paper, an infinitesimal vertical electric dipole (VED) will produce magnetic vector potential G/sub a//sup zz/ where the first and second superscript designate, respectively, the component of the vector potential and the direction of the source. The pulsating point charge associated with a VED will produce an electric scalar potential G/sub q//sup v/. From these potentials, one can compute both the horizontal and vertical fields generated by a VED. However, G/sub a//sup xx/ and G/sub q//sup h/, counterparts generated by a horizontal electric dipole (HED) in the x direction allow one to compute the horizontal fields only. Sommerfeld [1949] showed that assuming that the magnetic vector potential from an HED has only an x-component is insufficient to satisfy all boundary conditions for the fields, except in the homogeneous case, He then invented a z-component of the vector potential G/sub a//sup zx/ to correct this problem. The present authors continue by discussing a complex image method. >

Journal ArticleDOI
TL;DR: In this article, the influence of projective invariance on the renormalization properties of the theory is investigated and one-loop counter-terms are calculated in the most general case of interaction of gravity with a scalar field.
Abstract: We investigate the influence of projective invariance on the renormalization properties of the theory. One-loop counter-terms are calculated in the most general case of interaction of gravity with a scalar field.

Journal ArticleDOI
TL;DR: In this paper, a finite element modeling of 3D eddy currents in magnetically nonlinear media is described, where the magnetic vector potential A, with or without the electric scalar potential V, is used inside eddy current regions.
Abstract: A method for finite element modelling of transient 3D eddy currents in magnetically nonlinear media is described. The magnetic vector potential A, with or without the electric scalar potential V, is used inside eddy current regions, coupled to magnetic scalar potentials elsewhere. Time transient torque, current and flux values are compared to measurements taken from a rotational test rig. >

Journal ArticleDOI
TL;DR: In this article, the authors deal with the calculation of forces in 2 and 3 dimensions for magnetostatic problems using a vector- (2D) or scalar potential (3D) method.
Abstract: This paper deals with the calculation of forces in 2 and 3 dimensions for magnetostatic problems. For solutions of the Finite Integration Theory using a vector- (2D) or scalar potential (3D) a method is described to get consistent field solutions of B/spl I.oarr/ and H/spl I.oarr/ which considerably improves the accuracy of force calculation. Examples are given for tests and typical applications. >

Journal ArticleDOI
TL;DR: In this article, the authors derived two true generalizations of Newton's theory (a ten-fields and an eleven-fields) in terms of an explicit Lagrangian realization of the dynamics of a Riemannian three-space.
Abstract: In a preceding paper we developed a reformulation of Newtonian gravitation as a {\it gauge} theory of the extended Galilei group. In the present one we derive two true generalizations of Newton's theory (a {\it ten-fields} and an {\it eleven-fields} theory), in terms of an explicit Lagrangian realization of the {\it absolute time} dynamics of a Riemannian three-space. They turn out to be {\it gauge invariant} theories of the extended Galilei group in the same sense in which general relativity is said to be a {\it gauge} theory of the Poincare group. The {\it ten-fields} theory provides a dynamical realization of some of the so-called ``Newtonian space-time structures'' which have been geometrically classified by Kunzle and Kuchař. The {\it eleven-fields} theory involves a {\it dilaton-like} scalar potential in addition to Newton's potential and, like general relativity, has a three-metric with {\it two} dynamical degrees of freedom. It is interesting to find that, within the linear approximation, such degrees of freedom show {\it graviton-like} features: they satisfy a wave equation and propagate with a velocity related to the scalar Newtonian potential.

Journal ArticleDOI
TL;DR: In this paper, the scalar magnetic potential formulation of 3D eddy current problems with small skin depths is reduced to a weak Galerkin form and the finite element discretization of this form results in two (volume and surface) "stiffness" matrices.
Abstract: In the paper, impedance boundary conditions are represented in terms of scalar magnetic potential. This leads to a scalar magnetic potential formulation of three‐dimensional (3‐D) eddy current problems with small skin depths. The scalar potential formulation is then reduced to a weak Galerkin form. The finite element discretization of this form results in two (volume and surface) ‘‘stiffness’’ matrices. This approach completely avoids vectorial calculations in 3‐D eddy current analysis.