Electromagnetic fields and waves in vacuum

2018 ◽  
Author(s):  
J. Pierrus
Keyword(s):  
Electromagnetic Field ◽  
Transmission Lines ◽  
Electromagnetic Waves ◽  
Momentum Conservation ◽  
Time Dependent ◽  
Classical Electrodynamics ◽  
Faraday’S Law ◽  
Wave Guides ◽  
Current Densities ◽  
Energy And Momentum

In previous chapters four experimental laws of electromagnetism were encountered: Gauss’s law in electrostatics, Gauss’s law in magnetism, Faraday’s law and Ampere’s law. Now, in this chapter, these laws are generalized where appropriate to include the time-dependent charge and current densities ρ‎( r, t) and J ( r, t) respectively. The result is a set of four coupled differential equations—known as Maxwell’s equations— which provide the foundation upon which the theory of classical electrodynamics is based. One of the most important aspects which emerges from Maxwell’s theory is the prediction of electromagnetic waves, and an entire spectrum of electromagnetic radiation. Some of the properties of these waves travelling in unbounded vacuum are considered, as well as their polarization states, energy and momentum conservation in the electromagnetic field and also applications to wave guides and transmission lines.

scholarly journals Analysis on the Influence of Transmission Lines span on Passive Interference in Shortwave

2018 ◽  
Vol 64 ◽  
pp. 05004
Author(s):  
Ying Lu ◽  
Zhibin Zhao ◽  
Jian gong Zhang ◽  
Zheyuan Gan
Keyword(s):  
Electromagnetic Field ◽  
Transmission Line ◽  
Transmission Lines ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
Short Wave ◽  
Critical Distance ◽  
Observation Point ◽  
Radio Station ◽  
Passive Interference

The passive interference of transmission lines to nearby radio stations may affect the effective reception and transmission of radio station signals. Therefore, the accurate calculation of the electromagnetic scattering of transmission lines under the condition of external electromagnetic waves is the basis for determining the reasonable avoidance spacing of the two. For passive stations operating in short-wave frequencies, passive interference is mainly generated by the tower, and span is one of the most significant factors affecting passive interference. This paper uses the method of moments to carry out the passive interference calculations under normal circumstances, expounds the method of calculating the electromagnetic field of transmission line at the same time. And elaborates the method for calculating the electromagnetic field of the transmission line, obtains the space electric field intensity of the transmission line at the same working frequency and space location of the plane wave. Applying the approximate formula to calculate the formula for the span and critical distance between the observation point and the transmission line.

scholarly journals The quantum theory of dispersion in metallic conductors

1929 ◽  
Vol 124 (794) ◽  
pp. 409-422 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Electromagnetic Field ◽  
Quantum Theory ◽  
Isotropic Medium ◽  
Electromagnetic Waves ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Classical Electrodynamics ◽  
Metallic Conductivity

1. Formulation of the problem. - The propagation of electromagnetic waves in a homogeneous isotropic medium showing metallic conductivity has been treated phenomenologically on the basis of classical electrodynamics. If in Maxwell's equations for the electromagnetic field curl E = - 1/ c ∂B/∂ t , curl H = 1/ c (∂D/∂ t + 4πI), div D = 4πρ, div B = 0, we assume that D = εE, B = μH, I = σE, (1) where e is the dielectric constant, u the permeability and q the electrical conductivity, we get curl E = - μ/c ∂H/∂ t , curl H = 1/ c (ε ∂E/∂ t 4πσE), div E = 4πρ/ε. div H =0.

Classical electrodynamics as a distribution theory. II

1958 ◽  
Vol 54 (2) ◽  
pp. 258-264 ◽  
Author(s):  
J. G. Taylor
Keyword(s):  
Electromagnetic Field ◽  
Total Energy ◽  
Distribution Theory ◽  
Classical Electrodynamics ◽  
Definition Of ◽  
Energy And Momentum

ABSTRACTIn a previous paper by the author (3) it was shown how the theory of distributions of L. Schwartz enables a mathematically consistent formalism to be given for a system composed of point charges interacting through their classical electromagnetic field. In the present paper a definition of the energy and momentum of the field lying in a space-like surface is given, and it is shown that from this four-vector it is possible to derive the usual equation of conservation of total energy and momentum.

scholarly journals Formulation of Time-Fractional Electrodynamics Based on Riemann-Silberstein Vector

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 987
Author(s):  
Tomasz P. Stefański ◽  
Jacek Gulgowski
Keyword(s):  
Wave Propagation ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Momentum Conservation ◽  
Point Of View ◽  
Classical Electrodynamics ◽  
Classical Solutions ◽  
Systems With Memory ◽  
Energy And Momentum ◽  
With Memory

In this paper, the formulation of time-fractional (TF) electrodynamics is derived based on the Riemann-Silberstein (RS) vector. With the use of this vector and fractional-order derivatives, one can write TF Maxwell’s equations in a compact form, which allows for modelling of energy dissipation and dynamics of electromagnetic systems with memory. Therefore, we formulate TF Maxwell’s equations using the RS vector and analyse their properties from the point of view of classical electrodynamics, i.e., energy and momentum conservation, reciprocity, causality. Afterwards, we derive classical solutions for wave-propagation problems, assuming helical, spherical, and cylindrical symmetries of solutions. The results are supported by numerical simulations and their analysis. Discussion of relations between the TF Schrödinger equation and TF electrodynamics is included as well.

scholarly journals Time-dependent sources identification for transmission lines problems

2015 ◽  
Vol 4 (2) ◽  
pp. 9 ◽  
Author(s):  
J. Benoit ◽  
P. Bonnet ◽  
C. Chauvière ◽  
S. Girard
Keyword(s):  
Electromagnetic Field ◽  
Linear Combination ◽  
Transmission Lines ◽  
Real Life ◽  
Real Data ◽  
Time Profile ◽  
Time Dependent ◽  
Computational Domain ◽  
Sources Identification ◽  
Dependent Sources

This paper is devoted to introduce an extension to the Linear Combination of Configuration Fields (LCCF). This new numerical method was designed to compute the time profile of an electromagnetic source radiating a specified electromagnetic field in all or part of the computational domain, for a specified duration. Here, we extend this idea within the framework of a transmission lines network. The principle of the method is first validated numerically. Then we prospect the same ideas in a real-data experiment which shows that the method is ready for real-life investigations.

DISCONTINUOUS MOTION OF AN ELECTRIC PARTICLE

1945 ◽  
Vol 23a (2) ◽  
pp. 39-46
Author(s):  
W. H. Watson
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Waves ◽  
Optical Radiation ◽  
Discrete Series ◽  
Inertial Mass ◽  
Null Cone ◽  
Mass Energy ◽  
Electromagnetic Field Tensor ◽  
Energy And Momentum ◽  
Insight Into

At the outset this paper deals with a world-track which consists of a discrete series of events at which the particle may be found. The electric potential may change very rapidly in the vicinity of the null-cone with its vertex at the point–instant singularity, without requiring the usual electric current to sustain the wave of potential, provided that the electromagnetic field tensor is revised in accordance with equations previously proposed (5) to represent the non-optical radiation of energy and momentum. Such forms of potential represent the switching on and off of charge. Inertial mass, energy, and momentum are associated with the wave. Different possibilities for discontinuous motion of an electric particle occur, depending on the modes of its successive creations and annihilations.The model discussed exhibits the essential separation of space–time into two regions, in one of which the field is static and in the other it vanishes, and leads to new insight into the structure of electromagnetic field singularities as boundaries of the field which we may think of as propagated like electromagnetic waves in a wave-guide.Connection of these ideas with quantum theory is briefly discussed.

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