A flexible approach to modeling the storm time Region 2 and magnetopause currents

Abstract

We present flexible approaches to modeling the Region 2 (R2) Birkeland current system with the associated partial ring current (PRC) and the Chapman‐Ferraro currents for arbitrarily shaped magnetopauses. The R2 field‐aligned current sheet and the PRC are constructed with an array of overlapping conical diffuse current segments. The dawnside R2 current is connected to the duskside R2 current azimuthally in the equatorial plane, forming a spread‐out PRC. The Chapman‐Ferraro shielding field due to an arbitrary magnetopause shape (on the basis of empirical approximations) is derived as a linear combination of spherical harmonics and image dipoles by a least squares minimization. We generalize the Rice Field Model, a modular open field model, to include the effects of these current systems, which are important in the storm time magnetosphere. We demonstrate the feasibility and flexibility of these techniques by modeling a simple R2 Birkeland current and PRC system.