The investigators will combine coincident ground-based optical and radar data to simultaneously specify the average energy and energy flux of precipitating electrons and the resulting changes in the atomic oxygen concentration. The investigators will use data from past experimental campaigns at Sondre Stromfjord, Greenland, including electron densities measured by the incoherent scatter radar, zenith intensities of key emission features measured by multi-channel photometers, winds inferred from Fabry-Perot interferometer measurements, images from an all-sky camera, magnetic field variations from a chain of ground-based magnetometers, and data from polar-orbiting satellites. They will correlate time variations in atomic oxygen with the particle and Joule heating rates, estimated from models and coincident satellite and ground-based magnetometer data. These data will be used to study the thermospheric response to particle and Joule heating, plasma characteristics of pre-energized auroral electrons, production and loss associated with observed optical emission features, and populations and relative transition rates also associated with these emission features.
