V.L.F. propagation across the geomagnetic anomaly during S.I.D.s
Tipo
Artigo
Data de publicação
1967
Periódico
Journal of Atmospheric and Terrestrial Physics
Citações (Scopus)
6
Autores
Kaufmann P.
Schaal R.E.
Lopes W.
Arakaki L.
Schaal R.E.
Lopes W.
Arakaki L.
Orientador
Título da Revista
ISSN da Revista
Título de Volume
Membros da banca
Programa
Resumo
A number of S.I.D.s (sudden ionospheric disturbances) has been selected and analysed, in order to find some compatibility with the general form of the theory of waveguide mode propagation in an Earth-ionosphere spherical waveguide having an upper boundary characterized by a conductivity parameter derived from an exponential model. The v.l.f. (very low frequency) transmissions were received at a site located near the center of the South Atlantic Geomagnetic Anomaly, all of them crossing the region of the equatorial electrojet-and the results show that the general formulation may be used if the daytime upper boundary is less than 65 km. On the other hand the peculiar physical conditions found in the upper atmosphere along such paths possibly have an important influence on its shape and on the considered waveguide configuration, and they must be considered for getting a better understanding of the S.I.D. effects. Further experiments are suggested, emphazising the need of a more accurate knowledge of the dependence of the ionospheric parameter L on frequency. © 1967.