Two-dimensional Chapman-Ferraro Problem with neutral sheet: 1. The boundary

Abstract

An exact solution to a two-dimensional magnetosphere with tail and neutral sheet using the Chapman-Ferraro approximation has been found by mapping in the potential plane. The magnetic flux in the tail is an arbitrary parameter of the problem. Boundary and neutral sheet configurations are presented for several values of tail flux. It is found that the position of the neutral sheet and its return current on the outer boundary is very sensitive to the amount of magnetic flux in the tail. The relationship with the three-dimensional case is discussed, and it is concluded that the neutral sheet probably moves in and out by several earth radii. This suggests the following large-scale convective flow pattern for the magnetosphere. Between magnetospheric substorms, field lines are carried into the tail, which causes an increase in tail flux, an inward motion of the neutral sheet, and a two-celled ionospheric current system. The magnetospheric substorm then chops off the inner edge of the neutral sheet, returning the system to its initial topology.