scholarly journals On a Godel-type Nonstatic Cosmological Solution for Matter in an Electromagnetic Field

1967 ◽  
Vol 20 (6) ◽  
pp. 663 ◽  
Author(s):  
HM Raval
Keyword(s):  
Electromagnetic Field ◽  
Cosmological Model ◽  
Charge Density ◽  
Electromagnetic Fields ◽  
Maxwell Equations ◽  
Cosmological Solution ◽  
Anisotropic Fluid ◽  
Net Charge

Some solutions of the Einstein-Maxwell equations for gravitational and electromagnetic fields against the background of a rotating and either a stationary or an expanding cosmological model have been obtained. The details of one of these solutions have been given. The solution describes a cosmological model with rotation and shear. The model is initially stationary and then expanding. It is filled with anisotropic fluid and is pervaded by the electromagnetic field, the net charge density being zero.

scholarly journals Mimicking static anisotropic fluid spheres in general relativity

2016 ◽  
Vol 25 (02) ◽  
pp. 1650019 ◽  
Author(s):  
Petarpa Boonserm ◽  
Tritos Ngampitipan ◽  
Matt Visser
Keyword(s):  
Electromagnetic Field ◽  
Scalar Field ◽  
Charge Density ◽  
Perfect Fluid ◽  
Radial Pressure ◽  
Energy Conditions ◽  
Fluid Sphere ◽  
Anisotropic Fluid ◽  
Spherically Symmetric ◽  
Anisotropic Fluid Sphere

We argue that an arbitrary general relativistic static anisotropic fluid sphere, (static and spherically symmetric but with transverse pressure not equal to radial pressure), can nevertheless be successfully mimicked by suitable linear combinations of theoretically attractive and quite simple classical matter: a classical (charged) isotropic perfect fluid, a classical electromagnetic field and a classical (minimally coupled) scalar field. While the most general decomposition is not unique, a preferred minimal decomposition can be constructed that is unique. We show how the classical energy conditions for the anisotropic fluid sphere can be related to energy conditions for the isotropic perfect fluid, electromagnetic field, and scalar field components of the model. Furthermore, we show how this decomposition relates to the distribution of both electric charge density and scalar charge density throughout the model. The generalized TOV equation implies that the perfect fluid component in this model is automatically in internal equilibrium, with pressure forces, electric forces, and scalar forces balancing the gravitational pseudo-force. Consequently, we can build theoretically attractive matter models that can be used to mimic almost any static spherically symmetric spacetime.

Analysis on Lightning Electromagnetic Fields

2013 ◽  
Vol 401-403 ◽  
pp. 350-353 ◽  
Author(s):  
Pi Cui Zhang ◽  
Wei He ◽  
Liu Ling Wang ◽  
Li Feng Ma
Keyword(s):  
Electromagnetic Field ◽  
Spatial Distribution ◽  
Electromagnetic Fields ◽  
Maxwell Equations ◽  
Practical Significance ◽  
Lightning Protection ◽  
Perfect Conductor ◽  
Fundamental Theory ◽  
Lightning Current ◽  
The Earth

t is generally needed to know precisely spatial distribution of lightning electromagnetic fields in the lightning protection measurements. Therefore, the research on the lightning electromagnetic field is of practical significance. In this paper, the Maxwell equations were used to calculate and analyze the spatial distribution of lightning electromagnetic fields surrounding lightning current. And the expressions of lightning current electromagnetic fields were deduced under the assumption that the earth was under the condition of perfect conductor. The spatial distributions of the components of lightning electromagnetic fields have been plotted by Matlab. The results would provide fundamental theory for the research of lightning electromagnetic field and lightning protection measurements.

On a duality invariant action principle in vacuum electrodynamics

1970 ◽  
Vol 48 (20) ◽  
pp. 2423-2426 ◽  
Author(s):  
G. M. Levman
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Maxwell Equations ◽  
Lagrangian Density ◽  
Vacuum Field ◽  
Field Tensor ◽  
Field Equations ◽  
Invariant Action ◽  
Electromagnetic Field Tensor ◽  
Derivatives Of

Although Maxwell's vacuum field equations are invariant under the so-called duality rotation, the usual Lagrangian density for the electromagnetic field, which is bilinear in the first derivatives of the electromagnetic potentials, does not exhibit that invariance. It is shown that if one takes the components of the electromagnetic field tensor as field variables then the most general Lorentz invariant Lagrangian density bilinear in the electromagnetic fields and their first derivatives is determined uniquely by the requirement of duality invariance. The ensuing field equations are identical with the iterated Maxwell equations.

Hertzian electromagnetic potentials and associated gauge transformations

1955 ◽  
Vol 231 (1185) ◽  
pp. 250-263 ◽  
Keyword(s):  
Electromagnetic Field ◽  
General Theory ◽  
Gauge Transformation ◽  
Electromagnetic Fields ◽  
Maxwell Equations ◽  
Gauge Transformations ◽  
Material Medium ◽  
Electromagnetic Potentials ◽  
Complementary Function ◽  
New Type

In spite of the wide use of Hertzian potentials in special problems there appears to be no account of the general theory which is completely satisfactory—especially with regard to (i) the arbitrariness of the potentials and the relation between different equivalent representations of the same electromagnetic field, (ii) the derivation of the Hertzian potentials for such equivalent representations from the physical sources, and (iii) electromagnetic fields not in vacuo. It is the purpose of this paper to fill this gap. It is shown that the Hertzian potentials may be subjected to a new type of gauge transformation which leaves invariant the electromagnetic field they represent. The particular integrals of the inhomogeneous Maxwell equations are generalized, so that they may be subjected to a related gauge transformation which leaves invariant the physical sources of the field; this leads to a treatment of (ii) above, which appears to be new. Examples, including the Whittaker and Debye—Bromwich two-scalar representations, are given. Finally, the theorem is established that, for any electromagnetic field in any stationary material medium, the particular integral of Maxwell equations may be so chosen that in general the complementary function can be expressed in terms of only two scalar functions (components of Hertzian potentials), previously only known to hold for source-free regions in vacuo .

Coupled azimuthal modes propagating in current-carrying plasma waveguides

2011 ◽  
Vol 78 (2) ◽  
pp. 105-123 ◽  
Author(s):  
V. GIRKA ◽  
I. GIRKA ◽  
I. PAVLENKO ◽  
O. GIRKA ◽  
A. GIRKA
Keyword(s):  
Electromagnetic Field ◽  
Spatial Distribution ◽  
Linear Theory ◽  
Successive Approximation ◽  
Electromagnetic Fields ◽  
Maxwell Equations ◽  
Zero Approximation ◽  
Azimuthal Direction ◽  
Coupled Modes ◽  
Cylindrical Metal

AbstractThe paper is devoted to the theory of electromagnetic surface waves propagating along the azimuthal direction in cylindrical metal waveguides, which are filled with current-carrying plasmas. The problem is solved by the method of successive approximation. Adequacy of this method application is proved here. To study the coupling of ordinary (O-) and extraordinary (X-) azimuthal modes, the linear theory of the eigenazimuthal X- and O-modes is applied as zero approximation. Plasma particles are described in the framework of magneto-hydrodynamics, electromagnetic fields of the coupled azimuthal modes are determined from Maxwell equations. Spatial distribution of electromagnetic field of these coupled modes and their damping caused for different reasons are studied. Possibility to observe experimentally the phenomena, which accompany propagation of these coupled modes, is estimated numerically. Branches of their possible utilization are discussed as well.

scholarly journals The Physics of Tachyons III. Tachyon Electromagnetism

1994 ◽  
Vol 47 (4) ◽  
pp. 431
Author(s):  
Ross L Dawe ◽  
Kenneth C Hines
Keyword(s):  
Electromagnetic Field ◽  
Charge Density ◽  
Special Relativity ◽  
Electromagnetic Fields ◽  
Electric Charge ◽  
Current Density ◽  
Inertial Reference Frame ◽  
Vector Potentials ◽  
New Formulation ◽  
Extended Relativity

A new formulation of the theory of tachyons using the same two postulates as in special relativity is applied to electromagnetism. Tachyonic transformations of the electromagnetic fields E and B are rigorously derived from Maxwell's equations and are shown to be the same as for bradyonic transformations. Tachyonic transformations of current density, charge density, scalar and vector potentials are also derived and discussed. Tachyonic optics and the four-potential of a moving tachyonic charge are also discussed, along with generalised four-vector transformations and electromagnetic four-tensors in extended relativity. Use is made of a switching principle to show how tachyons automatically obey the law of conservation of electric charge in any inertial reference frame, even though the observed tachyon electric charge is not an invariant between observers. The electromagnetic field produced by a charged tachyon takes the form of a Mach cone, inside which the electromagnetic field is real and detectable, while outside the cone the field generated by the tachyon is imaginary and undetectable.

Measurements of the Net Charge Density of Space Plasmas

2021 ◽  
Author(s):  
Chao Shen ◽  
Yufei Zhou ◽  
Lai Gao
Keyword(s):  
Charge Density ◽  
Space Plasmas ◽  
Net Charge

SOLITARY WAVES OF THE NONLINEAR KLEIN-GORDON EQUATION COUPLED WITH THE MAXWELL EQUATIONS

2002 ◽  
Vol 14 (04) ◽  
pp. 409-420 ◽  
Author(s):  
VIERI BENCI ◽  
DONATO FORTUNATO FORTUNATO
Keyword(s):  
Electromagnetic Field ◽  
Solitary Wave ◽  
Electric Field ◽  
Solitary Waves ◽  
Maxwell Equations ◽  
Gordon Equation ◽  
Klein Gordon ◽  
Klein Gordon Equation

This paper is divided in two parts. In the first part we construct a model which describes solitary waves of the nonlinear Klein-Gordon equation interacting with the electromagnetic field. In the second part we study the electrostatic case. We prove the existence of infinitely many pairs (ψ, E), where ψ is a solitary wave for the nonlinear Klein-Gordon equation and E is the electric field related to ψ.

scholarly journals ELECTROMAGNETIC FIELDS OF CHARGED AND MAGNETIZED CYLINDRICAL CONDUCTORS IN NUT SPACE

2005 ◽  
Vol 14 (03n04) ◽  
pp. 687-695 ◽  
Author(s):  
B. J. AHMEDOV ◽  
A. V. KHUGAEV ◽  
N. I. RAKHMATOV
Keyword(s):  
Magnetic Field ◽  
Gravitational Field ◽  
Electromagnetic Fields ◽  
Electric Charge ◽  
Maxwell Equations ◽  
Analytic Solutions ◽  
Vertical Magnetic Field ◽  
General Relativistic ◽  
Azimuthal Current ◽  
Cylindrical Conductors

We present analytic solutions of Maxwell equations for infinitely long cylindrical conductors with nonvanishing electric charge and currents in the external background spacetime of a line gravitomagnetic monopole. It has been shown that vertical magnetic field arising around cylindrical conducting shell carrying azimuthal current will be modified by the gravitational field of NUT source. We obtain that the purely general relativistic magnetic field which has no Newtonian analog will be produced around charged gravitomagnetic monopole.

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