Ion energization and dynamics in the polar ionosphere

Thermal ion observations, made by the Suprathermal Ion Mass Spectrometer on the EXOS-D satellite, are used to estimate ion temperatures, ion densities, ion velocities, and the satellite potential to the plasma. In cusp region, ions are strongly heated to the perpendicular direction of local magnetic field lines and flow along the magnetic field lines. The field-aligned flows, the polar wind, are also observed in the polar cap region.