Understanding storm-time multi-scale ionospheric structures at mid-latitudes

The storm-time mid-latitude ionosphere is an important interface in the global geospace dynamic system, which is characterized by energy and momentum ingests at the auroral/polar latitudes. This interface is affected by these high-latitude processes while being adjacent to expanded low-latitude electrodynamic/dynamic disturbances.  In particular, the mid-latitude and subauroral ionosphere can exhibit far more complicated multi-scale density/flow structures and disturbances than might otherwise be expected during geospace storms, such as large-scale and medium-scale traveling ionospheric disturbances (TIDs), storm-enhanced density (SED) plume, and subauroral polarization stream (SAPS). This presentation will describe some recent storm-time observations of these multi-scale ionospheric structures as well as discuss the underlying magnetosphere-ionosphere-thermosphere drivers. These observations provide some new scenarios to advance the current understanding of mid-latitude and subauroral dynamic processes at both large-scale and meso-scale levels.