Dartmouth Events

Abstract: Contrary to our earlier concept, the Earth’s ionosphere constitutes a significant source of plasma in the magnetosphere. We present a composite picture of thermal and suprathermal ion outflows from the high-latitude ionosphere, focusing on oxygen and other heavy ion species. Based on observations from multiple ground and space-based platforms over five solar cycles, this picture underscores the multi-scale nature of the contributing ion acceleration and transport processes and their fundamental role in magnetosphere-ionosphere coupling. These include perpendicular and parallel acceleration in the mid (~1000-5000 km) or high-altitude auroral zone, and centrifugal acceleration in regions of curved or changing magnetic field at high altitudes (above ~3-4 Earth radii). A significant fraction of ion outflows remains cold in the magnetosphere, where their transport is strongly influenced by the interplanetary magnetic field and the prevailing convection electric field. We will discuss the gaps of our current knowledge on these processes in the light of recent satellite observations.