Swarm Electric Field Instruments' Thermal Ion Imagers: A Decade of Discovery

Abstract

The Swarm mission concept is innovative in its recognition that high-quality measurements of the geomagnetic field from LEO require accurate knowledge of Earth’s plasma environment, and furthermore that combined, precision measurements of fields, plasmas and neutral density from polar orbit provide a new window into ionosphere-thermosphere-magnetosphere (ITM) coupling and science. During the first decade of operations, event-based studies have led to new discoveries such as extreme plasma flows associated with the Birkeland current systems, the electrodynamic structure of multiple auroral arcs, the sub-auroral “STEVE” phenomenon, and the existence of standing Alfvén waves at equatorial latitudes. At the same time, the mission has accumulated an extensive database of measurements at high spatial resolution collected over a wide range of condition covering nearly a full solar cycle; these data have been used in longer-term statistical studies of plasma properties, high-latitude convection and ITM coupling via Poynting flux. As we enter the next decade of operations, the Swarm data are increasingly being used to inform empirical and physics-based models of the ionosphere; these in turn will comprise an important part of the long-term legacy of the Swarm mission. This talk will highlight scientific discoveries from the first decade of EFI operations, centred on observations of ion flows and associated electric fields from the EFI’s Thermal Ion Imagers, and made possible by a large and active community of collaborators.