Calculation methods of the electric and magnetic fields at the Earth's surface produced by a line current

Risto Pirjola; David Boteler

doi:10.1029/2001rs002576

Calculation methods of the electric and magnetic fields at the Earth's surface produced by a line current

Radio Science ◽

10.1029/2001rs002576 ◽

2002 ◽

Vol 37 (3) ◽

pp. 14-1-14-9 ◽

Cited By ~ 7

Author(s):

Risto Pirjola ◽

David Boteler

Keyword(s):

Magnetic Fields ◽

Calculation Methods ◽

Line Current ◽

Electric And Magnetic Fields

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THE ELECTRIC AND MAGNETIC FIELDS AT THE SURFACE OF A FLAT CONDUCTING EARTH IN THE NEAR FIELD OF AN OSCILLATING LINE CURRENT

Canadian Journal of Physics ◽

10.1139/p66-158 ◽

1966 ◽

Vol 44 (8) ◽

pp. 1923-1931 ◽

Cited By ~ 3

Author(s):

H. W. Dosso

Keyword(s):

Magnetic Fields ◽

Near Field ◽

Numerical Calculations ◽

Line Current ◽

The Earth ◽

Electric And Magnetic Fields ◽

Phase Angles

The electric and magnetic fields at the surface of a flat conducting earth in the near field of an oscillating line current are studied in this work. The equations for the amplitudes and phase angles developed by Law and Fannin (1961) were used for the numerical calculations. The source heights (h = 105 to 4 × 105 meters), the source frequencies (ƒ = 10−3 to 10 sec−1), and the earth conductivities (σ = 10−5 to 10 mho/m) considered are of interest in geophysics.

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Analogue model measurements of electromagnetic variations in the near field of an oscillating line current

Canadian Journal of Earth Sciences ◽

10.1139/e68-002 ◽

1968 ◽

Vol 5 (1) ◽

pp. 23-29 ◽

Cited By ~ 8

Author(s):

H. W. Dosso ◽

J. A. Jacobs

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Current Model ◽

Near Field ◽

Analogue Model ◽

Line Current ◽

Earth’S Mantle ◽

Electric And Magnetic Fields ◽

Sheet Current ◽

Conducting Zone

An analogue model for studying electromagnetic variations for an overhead oscillating line current is described. Measurements of electric and magnetic fields for model earth–sea interfaces are discussed and compared with results reported earlier for an overhead sheet current. A truncated cone representing a circular sea, a graphite wedge representing an ocean coastline, and a graphite wedge underlain by a graphite block representing an upwelling conducting zone in the earth's mantle near a sea coast are considered. In some cases the results for the line current model differ appreciably from those for the sheet current model, indicating that the nature of the source field can be an important factor in determining the behavior of the field components. The model measurements indicate that land–sea interfaces produce no appreciable anomalous magnetic fields at frequencies below 0.01 cps and hence the presence of the sea alone cannot account for coastal magnetic field anomalies. The results obtained for the model coastline structures tend to support the idea put forth by various workers that experimentally observed coastal magnetic field anomalies can in some cases be explained by assuming an upwelling conducting zone within the earth's mantle.

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