V.L.F. propagation across the geomagnetic anomaly during S.I.D.s

Kaufmann P.; Schaal R.E.; Lopes W.; Arakaki L.

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.

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.