Two-Dimensional Model of the Global Ionospheric Conductor

Abstract

To numerically simulate large-scale electric fields in the magnetosphere and ionosphere, the electrical conductivity problem is solved. The problem is substantially simplified due to the presence of a small parameter, the ratio of the conductivities in directions perpendicular and parallel to the magnetic field. Setting this parameter equal to zero makes magnetic field lines equipotential, so that the original three-dimensional problem reduces to a two-dimensional one. A comparison with the results of calculations performed within the framework of an alternative thin-layer model clearly demonstrates the advantages of using the conductivity anisotropy tensor rather than the smallness of the thickness of the ionosphere for constructing a two-dimensional approximation in a global simulation including the low-latitude ionosphere.