Magnetosphere-Ionosphere Coupling at Subauroral Latitudes (Invited)

On the night side of the inner magnetosphere and the conjugate ionosphere, there is a region where boundaries of several plasma populations of different origins and energy regimes (the plasmapause, the equatorward edge of the auroral oval, and the inner edge of the ring current) approximately coincide or overlap. This region is highly complex and dynamic. The magnetospheric hot plasmas and ionospheric-plasmaspheric cold populations are coupled through convection electric fields and auroral particle precipitation. Both convection (electric field) patterns and plasma densities are observed to be structured during geomagnetic disturbances, with Subauroral Polarization Streams (SAPS) near the auroral oval and plasma plumes (particularly prominent in TEC maps) extending to lower latitudes and in MLT from the nightside toward the afternoon sector. In this paper, we present an initial attempt to explain the causes of the observed ionospheric storm-time plasma structuring at mid and sub-auroral latitudes through self-consistent simulations using the Rice Convection Model. Specifically, we model the structure and longitudinal/UT dependence of SAPS structures in the duskside ionosphere, and how they may be related to meridional electron density transport postulated to be responsible for large storm-time TEC structuring in the afternoon-to-dusk MLT sector.