Ionospheric Storm‐Enhanced Density Plumes

Large-scale dayside increases in ionospheric density and total electron content (TEC) are observed at low, mid, and auroral latitudes in the early stages of geomagnetic storms. TEC increases as disturbance electric fields and neutral winds uplift the F region into a region of reduced recombination. Advection carries nightside plasma across the sunset terminator and draws out plumes of storm-enhanced density (SED plumes) that stretch from the dusk sector to the noontime cusp ionosphere. The SED plume cannot be considered in isolation from other disturbance effects since it is a part of the more widespread interconnected geospace system response to solar-wind forcing. This focused review addresses the history and current understanding of the SED plume and its role in the redistribution of ionosphere plasma in the geospace system.