Ionospheric traces of plasmaspheric plumes

The plasmasphere is a torus of cold plasma ‘frozen’ into the Earth’s magnetic field, sourced from the ionosphere. Drainage channels, called plumes are formed during disturbed periods by the modified electric field. While plumes have been primarily observed near the equator, the electric field driving then acts along the entire geomagnetic field line, setting the plasma within a complete drift shell into motion. Ionospheric evidence of this process is found in the so-called Storm-Enhanced-Density plumes, which also exhibit density surplus compared to the background. These findings led to the establishment of the geospace plume concept. However, this same process creates other features in the ionosphere, like the midlatitude trough, a zone of depleted plasma density. The relationship between plasmaspheric plumes and the ionospheric trough has been neglected in previous studies. Our findings challenge the current understanding of the geospace plume concept and underscore the need for its refinement.