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Simplified formulas for ELF propagation at shorter distances
Author(s) -
Bannister Peter R.
Publication year - 1986
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs021i003p00529
Subject(s) - ionosphere , wavelength , daytime , physics , range (aeronautics) , dipole , computational physics , wave propagation , electrical impedance , optics , schumann resonances , geodesy , geology , geophysics , atmospheric sciences , materials science , quantum mechanics , composite material
It is the purpose of this article to present new formulas for ELF electric and magnetic dipole propagation in the earth‐ionosphere waveguide. These new formulas extend the results of Wait and Galejs, which are valid for measurement distances greater than approximately three ionospheric reflecting heights, to the quasi‐near field range, which is defined as the range where the measurement distance is greater than an earth wavelength, but much less than free‐space wavelength. These new formulas will be particularly applicable in the range of approximately 20 to 300 km from the source. We will also present plots of the VED and HED (or HMD) radial wave impedance versus distance for both daytime and nighttime propagation conditions. These plots show a substantial variation in the radial wave impedances for distances less than 1,000 kilometers. We will also show that there is a unique distance where the minimum value of the VED radial wave impedance occurs.