Open AccessModelling of three‐dimensional current systems associated with magnetospheric substorms
Author(s) -
Kisabeth Jerry L.,
Rostoker Gordon
Publication year - 1977
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1977.tb01310.x
Subject(s) - substorm , electrojet , physics , magnetosphere , geophysics , perturbation (astronomy) , electromagnetic induction , ionosphere , magnetic field , earth's magnetic field , current loop , current (fluid) , computational physics , classical mechanics , mechanics , quantum mechanics , electromagnetic coil , thermodynamics
Summary It is now well accepted that magnetic field perturbations associated with polar magnetic substorms can be modelled by a three‐dimensional equivalent current loop involving an electrojet segment in the high‐latitude ionosphere linked to the outer magnetosphere by currents flowing parallel to magnetic lines of force. In this paper we present techniques for quantitative evaluation of the magnetic field perturbation at any point in space outside of the region of current flow. The technique is developed using the Biot–Savart Law and analytical expressions for the three components ( H, D, Z ) of the magnetic perturbation at the Earth's surface are developed. Assuming the Earth to be represented by an infinitely conducting sphere covered by a perfect insulator to some arbitrary depth, the time independent induction problem is treated and analytical expressions for H, D , and Z corrected for Earth induction are developed. The modelling technique is applied to three substorm events and the results provide an accurate and comprehensive indicator of the character and spatial extent of the inducing current system associated with magnetospheric substorms.