Premium
VLF Fields of Elevated Sources
Author(s) -
Galejs Janis
Publication year - 1970
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/rs005i008p01163
Subject(s) - electric field , dipole , amplitude , ionosphere , physics , daytime , magnetic dipole , transverse plane , anisotropy , geophysics , computational physics , electric dipole moment , optics , geodesy , geology , atmospheric sciences , structural engineering , quantum mechanics , engineering
An anisotropic ionosphere causes coupling between TE and TM modes; for any given mode the field components of a horizontal electric dipole remain finite for both the axial and endfire directions. During the daytime the ionospheric anisotropy is relatively weak, and the vertical electric fields E r of an elevated horizontal electric dipole exhibit a minimum near the broadside direction for west‐to‐east (WE) and (at short distances) for east‐to‐west (EW) propagation; during nighttime the fields exhibit maximum values near the broadside direction. For elevated sources and observation points, the transverse electric horizontal field component E ф of a horizontal electric dipole becomes comparable to E r of a vertical electric dipole. Inclined electric dipoles exhibit amplitude variations of the vertical electric fields E r with changes of direction relative to the dipole axis. The amplitude variations are particularly pronounced for the EW direction of nighttime propagation.