Current model used for inversion. Currents 1 … N
shown following lines of constant quasi-dipole latitude, with the satellite crossing the magnetic equator (shown as current j). Origin O represents the Earth’s center with vector r
pointing to linear current segment k of arc current j, and r
pointing to satellite observation point i. Unit current vector I
shown in enlarged region with relevant parameters (see text). Basis vectors and are shown for use during the modeling step (Section 7).