Accession Number : ADA135890

Title :   Propagation of ELF (Extremely Low Frequencies) Waves in the Spherical Earth-Ionosphere Waveguide with Transverse and Longitudinal Variation of Properties.

Descriptive Note : Analysis rept. 1979-1983,

Corporate Author : NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA

Personal Author(s) : Shellman,C H

PDF Url : ADA135890

Report Date : 14 Jun 1983

Pagination or Media Count : 197

Abstract : A formulation is described for finding the vertical E-field in the spherical earth-ionosphere waveguide at extremely low frequencies (elf). A very general model of propagation parameters is allowed since values of the eigenangles and of the excitation factors are specified at elements of a mesh point array that may extend throughout the lateral extent of the spherical-shell guide the solution is based on the condition that the vertical E-field must satisfy the two-dimensional wave equation in the vicinity of each mesh point. Eigensolutions are found for ranges from the transmitter for which there is no transverse variation of properties, and these are combined with the more general solution which applies to the region of transverse inhomogeneity. Two examples are given to illustrate both a symmetrical and nonsymmetrical case. It is expected that use of the formulation will make it possible to describe the effects of inhomogeneities such as the auroral zone, land-sea boundaries, the day-night terminator and man-made disturbances to the ionosphere on the amplitude and phase of the vertical E-field. (Author)

Descriptors :   *Electromagnetic wave propagation, Extremely low frequency, Aurorae, Polar regions, Wave equations, Ionospheric propagation, Waveguides

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation
      Non-radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE