scholarly journals FDTD analysis of ELF radio wave propagation in the spherical Earth-ionosphere waveguide and its validation based on analytical solutions

2021 ◽  
Author(s):  
Volodymyr Marchenko ◽  
Andrzej Kulak ◽  
Janusz Mlynarczyk

Abstract. The FDTD model of electromagnetic wave propagation in the Earth-ionosphere cavity was developed under assumption of axisymmetric system, solving the reduced Maxwell’s equations in a 2D spherical coordinate system. The model was validated on different conductivity profiles for the electric and magnetic field components for various locations on Earth along the meridian. The characteristic electric and magnetic altitudes, the phase velocity and attenuation rate were calculated. We compared the results of numerical and analytical calculations and found good agreement between them. The undertaken FDTD modeling enables us to analyze the Schumann resonances and the propagation of individual lightning discharges occurring at various distances from the receiver. The developed model is particularly useful when analyzing ELF measurements.

1972 ◽  
Vol 50 (20) ◽  
pp. 2402-2409 ◽  
Author(s):  
James R. Wait

Propagation along a thin dielectric coated wire parallel to the interface between two homogeneous half-spaces is considered. The solution accounts for the presence of the interface provided the coating radius is small compared with the distance to the interface. The final results are simplified in form when dealing with long insulated antennas buried in the earth and operating at low frequencies. Some numerical data are provided for a representative set of conditions. It is found that the presence of the air/earth interface will modify the propagation constant; in some cases the attenuation rate may be increased over that for an infinite medium.


Geophysics ◽  
1968 ◽  
Vol 33 (2) ◽  
pp. 346-353 ◽  
Author(s):  
Ajit K. Sinha

The problem of electromagnetic wave propagation from an oscillating magnetic dipole placed over a uniaxially anisotropic earth has been considered. Formal expressions for the vector potentials inside the earth have been derived. It has been shown that for a vertical magnetic dipole, the field components are identical to those in the case of an isotropic medium in which the conductivity is the “horizontal or longitudinal conductivity.” For a horizontal dipole, directed along the x axis, it has been shown that the vector potential inside the earth will have a y component as well as x and z components. Formal expressions for the vector potentials in air have been obtained for the case of a horizontal magnetic dipole. However when the conductivity of air is considered to be negligibly small, the field components are not affected by the anisotropy.


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