General solutions of Maxwell's equations for signals in a lossy medium. I. Electric and magnetic field strengths due to electric exponential ramp function excitation

The electromagnetic fields affecting the personnel during the maintenance of the traction network from the leiter are considered. The results obtained during calculations using the methodology developed at IrGUPS and implemented in the Fazonord software package show that the electric and magnetic field strengths exceed the permissible levels for electrical personnel

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Two-dimensional hybrid model for magnetic field calculation in electrical machines: exact subdomain technique and magnetic equivalent circuit

COMPEL The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ◽

10.1108/compel-01-2021-0008 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Brahim Ladghem Chikouche ◽

Kamel Boughrara ◽

Dubas Frédéric ◽

Rachid Ibtiouen

Keyword(s):

Magnetic Field ◽

Maxwell’S Equations ◽

Maxwell's Equations ◽

Current Density Distribution ◽

Electrical Machines ◽

Field Calculation ◽

Two Dimensional ◽

Content Type ◽

The Magnetic Field ◽

Load Conditions

Purpose The purpose of this paper is to propose a two-dimensional (2-D) hybrid analytical model (HAM) in polar coordinates, combining a 2-D exact subdomain (SD) technique and magnetic equivalent circuit (MEC), for the magnetic field calculation in electrical machines at no-load and on-load conditions. Design/methodology/approach In this paper, the proposed technique is applied to dual-rotor permanent magnet (PM) synchronous machines. The magnetic field is computed by coupling an exact analytical model (AM), based on the formal resolution of Maxwell’s equations applied in subdomains, in regions at unitary relative permeability with a MEC, using a nodal-mesh formulation (i.e. Kirchhoff's current law), in ferromagnetic regions. The AM and MEC are connected in both directions (i.e. r- and theta-edges) of the (non-)periodicity direction (i.e. in the interface between teeth regions and all its adjacent regions as slots and/or air-gap). To provide accurate solutions, the current density distribution in slot regions is modeled by using Maxwell’s equations instead to MEC and characterized by an equivalent magnetomotive force (MMF) located in the slots, teeth and yoke. Findings It is found that whatever the iron core relative permeability, the developed HAM gives accurate results for both no-load and on-load conditions. Finite element analysis demonstrates the excellent results of the developed technique. Originality/value The main objective of this paper is to achieve a direct coupling between the AM and MEC in both directions (i.e. r- and theta-edges). The current density distribution is modeled by using Maxwell’s equations instead to MEC and characterized by an MMF.

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Extension of the electrodynamics in the presence of the axion and dark photon

International Journal of Modern Physics A ◽

10.1142/s0217751x1950012x ◽

2019 ◽

Vol 34 (03n04) ◽

pp. 1950012 ◽

Cited By ~ 3

Author(s):

Fa Peng Huang ◽

Hye-Sung Lee

Keyword(s):

Magnetic Field ◽

Maxwell’S Equations ◽

Wave Equations ◽

Maxwell's Equations ◽

Dark Photon

We present the extended electrodynamics in the presence of the axion and dark photon. We derive the extended versions of Maxwell’s equations and dark Maxwell’s equations (for both massive and massless dark photons) as well as the wave equations. We discuss the implications of this extended electrodynamics including the enhanced effects in the particle conversions under the external magnetic or dark magnetic field. We also discuss the recently reported anomaly in the redshifted 21 cm spectrum using the extended electrodynamics.

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A theory of magnetic-like fields for viscoelastic fluids

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.50 ◽

2019 ◽

Vol 865 ◽

pp. 460-491

Author(s):

Thibault Vieu ◽

Innocent Mutabazi

Keyword(s):

Magnetic Field ◽

Stress Tensor ◽

Maxwell’S Equations ◽

Maxwell's Equations ◽

Viscoelastic Fluids ◽

Point Of View ◽

Viscoelastic Flows ◽

Maxwell Stress Tensor ◽

Viscoelastic Instability ◽

Theoretical Issues

We formulate the Oldroyd-B model for viscoelastic fluids in terms of magnetic-like fields obeying a set of equations analogous to Maxwell’s equations. In the limit of infinite relaxation time for the polymer, the polymeric stress tensor can be identified with the Maxwell stress tensor of a magnetic field. Away from this asymptotic case, the stress tensor of the polymer cannot be decomposed in terms of a tensor product of a magnetic field any more and several theoretical issues arise. We show that the analogy between the Oldroyd-B model and Maxwell’s equations can still be rigorously extended provided that one defines three magnetic-like fields obeying Maxwell’s equations with magnetic currents and charges. This solves the theoretical caveats and leads to a better understanding of the viscoelastic instability. In particular, we evidence a gauge symmetry which unifies some previous works, and we investigate several gauge choices. As an illustration we apply our method to viscoelastic Taylor–Couette flow but this theory of ‘viscoelastic fields’ is general and may be useful in a large variety of viscoelastic flows. The present study may also be of interest from the electromagnetic point of view, as it provides real systems possessing magnetic-like charges (monopoles) and currents.

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General solutions of equations of some geophysical importance

Bulletin of the Seismological Society of America ◽

10.1785/bssa0490030273 ◽

1959 ◽

Vol 49 (3) ◽

pp. 273-283

Author(s):

H. Takeuchi

Keyword(s):

Viscous Fluid ◽

Elastic Body ◽

Maxwell’S Equations ◽

Maxwell's Equations ◽

Equations Of Motion ◽

Incompressible Viscous Fluid ◽

Stationary Motion ◽

General Solutions ◽

Isotropic Elastic Body ◽

Solutions Of Equations

abstract General solutions are obtained in rectangular, circular cylindrical, and spherical co�nates for the equations of motion of a homogeneous isotropic elastic body (in § 2), the equations of the corresponding statical deformations (§ 3), the equations of motion of an incompressible viscous fluid (§ 4), the equations of the corresponding stationary motion (§ 5), and Maxwell's equations for a homogeneous isotropic conductor (§ 6).

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