This project will investigate plasma structuring on an intermediate spatial scale along the edges of mid-latitude ionosphere disturbances known as storm enhanced density (SED) using data-assimilative models. Although this topic has received attention only recently (relative to high- and low-latitude phenomena), improved understanding of SED generation and development is important for improving space-based communication and navigation capabilities. The project will use numerical models (IDA4D and EMPIRE) in order to study the spatial structuring of SEDs along with their physical drivers. Auxiliary data sets -- such as field-aligned plasma velocities measured by the Millstone Hill incoherent scatter radar, DMSP satellite data, estimated drift speeds from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) model, and total electron content measurements from GPS -- will also be used for cross-comparison with the model results.