Electromagnetic Field Caused by an Auroral Electrojet Current System Model

  • R. J. Pirjola
  • L. V. T. Häkkinen


A theoretical model of the auroral electrojet current system is discussed. The model contains a horizontal sheet electrojet of a finite length with a Gaussian transverse distribution of the current, and geomagnetic-field-aligned currents that make the divergence of the total current vanish. The time dependence is harmonic, and a harmonic spatial dependence along the electrojet is assumed. Induction in the earth is included by applying a homogeneous or four-layer model. Exact formulas expressing the electromagnetic field on the earth’s surface are used. Examples of the magnitudes of the field components are given. Particular attention is paid to the magnetotelluric apparent resistivity near an electrojet system, and it is indicated that incorrect results of the structure of the earth may be obtained if source effects are neglected in a magnetotelluric study.


Sheet Current Apparent Resistivity Finite Length Electromagnetic Induction Layered Half Space 
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Copyright information

© Springer-Verlag Tokyo 1991

Authors and Affiliations

  • R. J. Pirjola
    • 1
  • L. V. T. Häkkinen
    • 1
  1. 1.Geophysics DepartmentFinnish Meteorological InstituteHelsinkiFinland

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