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.

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 Electromagnetic field measurements in ULF-ELF-VLF [0.001 Hz–100 KHz] bands

2008 ◽  
Vol 14 ◽  
pp. 69-73 ◽  
Author(s):  
P. Palangio ◽  
F. Masci ◽  
M. Di Persio ◽  
C. Di Lorenzo
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Frequency Band ◽  
Seismic Activity ◽  
Central Italy ◽  
Field Measurements ◽  
Wide Band ◽  
The Earth ◽  
Innovative Technique ◽  
Electromagnetic Signals

Abstract. We are reporting the technological and scientific objectives of the MEM project. The MEM project has been activated in the INGV Observatory of L'Aquila to create in Central Italy a network of observatories in order to monitoring the electromagnetic signals in the frequency band [0.001 Hz–100 kHz]. Some examples of the instrumentation developed in the frame of the project are reported. An innovative technique, based on the wide band interferometry is proposed to obtain detailed information concerning the several detected electromagnetic sources. Moreover, data from each station will be elaborated to investigate different sectors as the structure of ground electric conductibility, the electromagnetic phenomena connected with seismic activity, the separation of the electromagnetic fields originated in the Earth's interior and the electromagnetic phenomena originated in the magnetosphere, in the ionosphere and in the Earth-ionosphere cavity.

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.

Modeling of artificially triggered lightning currents by multi-peaked analytically extended functions

2018 ◽  
Vol 37 (4) ◽  
pp. 1354-1365
Author(s):  
Vesna Javor ◽  
Karl Lundengård ◽  
Milica Rančić ◽  
Sergei Silvestrov
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Wire Antenna ◽  
Lightning Protection ◽  
Approximation Procedure ◽  
Content Type ◽  
Lightning Channel ◽  
Triggered Lightning ◽  
Lightning Discharges ◽  
Extended Function

Purpose This paper aims to present the approximation of lightning currents waveshapes by the multi-peaked analytically extended function (MP-AEF) for the experimentally measured channel-base currents in the artificially triggered lightning discharges. Modified transmission line model of lightning return strokes having the channel current both linearly decaying and sinusoidally changing with height (MTLSIN) is used to calculate the lightning electromagnetic field. Design/methodology/approach MP-AEF’s parameters for the artificially triggered lightning channel-base currents are calculated by using Marquardt least squares method (MLSM). Lightning electromagnetic fields are calculated based on electromagnetic theory relations, thin-wire antenna model of the vertical lightning channel and the assumption of the perfectly conducting ground. MTLSIN model as an engineering model of lightning strokes is used to obtain the electric field results as these are simultaneously measured in rocket-triggered lightning experiments together with the channel-base currents. Findings MP-AEF approximates multi-peaked pulse waveshapes. Some important function parameters are chosen prior to the approximation procedure, such as current peaks and the corresponding time moments of those peaks, which presents an advantage in comparison to other functions. The desired accuracy of approximation is obtained by choosing an adequate number of function terms. MLSM is used for the estimation of unknown parameters. Using MTLSIN model, the influence of the channel height and return stroke speed on the lightning electromagnetic field waveshape is analyzed in this paper. Research limitations/implications MP-AEF may be used for approximation of various multi-peaked waveshapes. It has no errors in the points of maxima which is important for the lightning protection systems design. MTLSIN model may be validated by using simultaneously measured lightning electromagnetic fields at various distances from the channel and for channel heights estimated in the experiments. It is also possible to approximate measured current derivatives by MP-AEF and use them for further computation. Originality/value MTLSIN model is proposed in this paper for the evaluation of lightning electromagnetic fields induced by artificially triggered lightning discharges. The procedure is based on the approximation of lightning channel-base currents by the multi-peaked analytically extended function previously proposed by the authors. This function may be used not only for representing lightning currents but also for other waveshapes as current derivatives, electric and magnetic fields and their derivatives, which are all important for the lightning protection design. MTLSIN gives lightning electromagnetic fields results which are in better agreement with measured fields than those obtained by other models from literature.

Electromagnetic Field of Accelerated Charges in Inertial Frames with Substratum Flow

1990 ◽  
Vol 45 (5) ◽  
pp. 749-755
Author(s):  
H.E. Wilhelm
Keyword(s):  
Electromagnetic Field ◽  
Charged Particle ◽  
Maxwell Equations ◽  
Inertial Frame ◽  
Field Equations ◽  
Velocity Of Light ◽  
The Earth ◽  
Inertial Frames ◽  
Em Field

Abstract By means of the generalized Galilei covariant EM field equations, the EM potentials and EM fields of a charged particle moving with an arbitrary nonuniform velocity v(t) in an inertial frame with substratum flow w are calculated. It is shown that the dynamic EM fields are excitations of the EM ether caused by the motion v(t) - w of the charge relative to the wave carrier with velocity w. Qualitatively and quantitatively significant EM inductions and convective deformations of EM fields by the ether flow w exist in inertial frames with ether velocities w~c0 comparable to the velocity of light. For many terrestrial applications, the ordinary Maxwell equations agree in good approximation with the Galilei covariant EM field equations since w/c0~ 10-3 on the earth

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.

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 .

scholarly journals The perturbation of electromagnetic fields at distances that are large compared with the object's size

2014 ◽  
Vol 80 (3) ◽  
pp. 865-892 ◽  
Author(s):  
Paul D Ledger ◽  
William R B Lionheart
Keyword(s):  
Magnetic Fields ◽  
Electromagnetic Fields ◽  
Asymptotic Expansions ◽  
Low Frequency ◽  
Perfect Conductor ◽  
Small Object ◽  
Leading Order ◽  
Material Parameters ◽  
Electric And Magnetic Fields

Abstract We rigorously derive the leading-order terms in asymptotic expansions for the scattered electric and magnetic fields in the presence of a small object at distances that are large compared with its size. Our expansions hold for fixed wavenumber when the scatterer is a (lossy) homogeneous dielectric object with constant material parameters or a perfect conductor. We also derive the corresponding leading-order terms in expansions for the fields for a low-frequency problem when the scatterer is a non-lossy homogeneous dielectric object with constant material parameters or a perfect conductor. In each case, we express our results in terms of polarization tensors.

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.

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