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Propagation of ELF and VLF Waves Below a Generally Anisotropic Ionosphere
Author(s) -
Galejs Janis
Publication year - 1968
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 - 10.1002/rds196838781
Subject(s) - ionosphere , attenuation , phase velocity , wave propagation , physics , very low frequency , azimuth , earth–ionosphere waveguide , anisotropy , computational physics , geophysics , geology , ionospheric heater , optics , astronomy
The mode analysis of ELF and VLF waves has been generalized to allow arbitrary directions of propagation below a curved stratified ionosphere with a dipping static magnetic field. In the ELF range, the propagation parameters are changed almost linearly with the azimuthal angle ϕ by varying the direction of propagation from east to west. In the VLF range, the phase velocity exhibits its maximum value for propagation in south‐and‐north direction; and minimum values occur for propagation toward west. Also, maximum attenuation rates occur for propagation toward the west. Measured interference distances D of the two lowest waveguide modes are explained using nighttime ionosphere models that exhibit sharp density gradients in the height range from go to 85 km.