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ULF/ELF electromagnetic fields generated along the seafloor interface by a straight current source of infinite length
Author(s) -
Inan A. S.,
FraserSmith A. C.,
Villard O. G.
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/rs021i003p00409
Subject(s) - seabed , electromagnetic field , seafloor spreading , geology , field (mathematics) , plane (geometry) , boundary (topology) , magnetic field , geophysics , near and far field , current (fluid) , geometry , acoustics , computational physics , physics , optics , mathematical analysis , mathematics , oceanography , quantum mechanics , pure mathematics
Propagation of ULF/ELF electromagnetic fields along the seafloor interface (assumed to be a plane boundary separating two semi‐infinite conducting media) is considered. Earlier expressions for the electromagnetic fields generated by a straight current source of infinite length are applied to the sea/seabed interface. The field components are calculated numerically and are compared to the field components in seawater of infinite extent. At the seafloor boundary, the fields can propagate longer distances because of the lower seabed conductivities. The new horizontal component of the magnetic field generated as a result of the existence of the sea/seabed interface becomes larger than the vertical component of the magnetic field at large distances; it is also more sensitive to the conductivity of the seabed at low frequencies. The results indicate that there is an optimal frequency at which two of the field components have a maximum field intensity at a certain distance from the source. Some practical applications are discussed.