Atom focalization by classical fields The interaction between a two-level atom and a single mode of the electromagnetic field (EMF) is governed by the semiclassical hamiltonian is the dipole moment operator, where £d is the unitary vector along the direction of quantization, p is the element of the transition matrix between the levels e (excited) […]

# Electromagnetic Waves

## Simulation and Analysis of Transient Processes in Open Axially-symmetrical Structures: Method of Exact Absorbing Boundary Conditions (Electromagnetic Waves) Part 1

Introduction Present day methodologies for mathematical simulation and computational experiment are generally implemented in electromagnetics through the solution of boundary-value (frequency domain) problems and initial boundary-value (time domain) problems for Maxwell’s equations. Most of the results of this theory concerning open resonators have been obtained by the frequency-domain methods. At the same time, a rich […]

## Simulation and Analysis of Transient Processes in Open Axially-symmetrical Structures: Method of Exact Absorbing Boundary Conditions (Electromagnetic Waves) Part 2

Far-field zone problem. Extended and remote sources As we have already mentioned, in contrast to approximate methods based on the use of the Absorbing Boundary Conditions or Perfectly Matched Layers, our approach to the effective truncation of the computational domain is rigorous, which is to say that the original open problem and the modified closed […]

## Fractional Operators Approach and Fractional Boundary Conditions (Electromagnetic Waves) Part 1

Introduction Tools of fractional calculus including fractional operators and transforms have been utilized in physics by many authors (Hilfer, 2000). Fractional operators defined as fractionalizations of some commonly used operators allow describing of intermediate states. For example, fractional derivatives and integrals (Oldham & Spanier, 1974; Samko et al., 1993) are generalizations of derivative and integral. […]

## Fractional Operators Approach and Fractional Boundary Conditions (Electromagnetic Waves) Part 2

Physical characteristics We consider such electrodynamic characteristics of the scattered field as the radiation pattern (RP), monostatic radar cross-section (MRCS) and surface current densities depending on the coefficients f^ . The scattered field Esz (x, y) in the far-zone kr in the cylindrical coordinate system is expressed as where the upper sign is chosen for, […]

## Atmospheric Refraction and Propagation in Lower Troposphere (Electromagnetic Waves) Part 1

Introduction Influence of atmospheric refraction on the propagation of electromagnetic waves has been studied from the beginnings of radio wave technology (Kerr, 1987). It has been proved that the path bending of electromagnetic waves due to inhomogeneous spatial distribution of the refractive index of air causes adverse effects such as multipath fading and interference, attenuation […]

## Atmospheric Refraction and Propagation in Lower Troposphere (Electromagnetic Waves) Part 2

Refractivity statistics As already mentioned, the physical processes in troposphere are complex enough to allow only statistical description of spatial and temporal characteristics of atmospheric refractivity. Nevertheless the statistics of important refractivity parameters such as an average vertical gradient are extremely useful in practical design of terrestrial radio paths when the long term statistics of […]

## Atmospheric Attenuation due to Humidity (Electromagnetic Waves) Part 1

Introduction Humidity remains in the atmosphere even on bright days. Water of all three states can be found naturally in the atmosphere: liquid (rain, fog, and clouds), solid (snowflakes, ice crystals), and gas (water vapour). Water in any state is an obstacle in the link of the electromagnetic wave. When the wave passes through the […]

## Atmospheric Attenuation due to Humidity (Electromagnetic Waves) Part 2

Calculation of the specific cloud attenuation The specific cloud attenuation is a function of clouds’ liquid water content and a coefficient, which is a function of frequency and temperature. In this case, the main problem is the value of clouds’ water content, because the direct measurements at a point in space are problematic. In cases […]

## Effects of Interaction of Electromagnetic Waves in Complex Particles Part 1

Introduction The majority of natural materials (rocks, soil, wood, etc.) are inhomogeneous and have a complex structure. Very often they are conglomerates or aggregates, i.e. made of small grains stuck together. This is especially typical for planetary aerosols and all types of cosmic dust (interstellar, circumstellar, interplanetary, cometary, etc.). Cosmic dust, specifically, cometary will be […]