Multi-scale investigation of low-altitude ion upflow and electron temperature correlations in the cusp/cleft ionosphere

Theoretically, the vertical motion of the ionosphere within and near the polar caps can influence the rate of atmospheric loss to space, yet the precise nature of the relationships between energy and momentum inputs and the resulting upflow and outflow are poorly characterized observationally within the ionosphere. A key mechanism involves ion vertical bulk acceleration (and consequent upflow at speeds up to several km/s) driven by ionospheric electron heating associated with magnetosheath electron precipitation in the cusp/cleft. Characterizing the spatial scales at which the electron precipitation drives upflow should provide insight into the process, and help constrain models. We apply several analysis techniques to the Swarm Electric Field Instrument measurements to investigate correlations between low-altitude ion upflow and electron temperature at spatial scales from several km to hundreds of km in the terrestrial cusp/cleft ionosphere.