The inclusion of SAPS in the inner-magnetospheric electric field description

The sub-auroral polarization stream, or, SAPS, is a latitudinally narrow channel of enhanced westward plasma drift located at the inner edge of the electron plasma sheet. Its dynamics and morphology are controlled by the coupled magnetosphere-ionosphere system. The mid-latitude electric field associated with the channel is an important feature of any inner-magnetospheric electric field (IMEF) description. Existing IMEF descriptions often do not include SAPS (e.g., the Volland-Stern model). We present an effort to advance semi-empirical SAPS modeling efforts by examining the spatio-temporal evolution of SAPS during geomagnetic storms and substorms using the publicly available Defense Meteorological Satellite Program's (DMSP) Midnight Boundary Index (MBI) and SSIES ion drift meter datasets, and the Cluster electric field datasets. We compare the DMSP/Cluster SAPS characteristics to existing statistical descriptions of SAPS. We also explore the marriage of SAPS models to existing IMEF models, such as Volland-Stern and UNH-IMEF.