NASA launched a payload of five satellites on Saturday that will orbit Earth for the next two years to study auroras in the magnetosphere. (Click here to watch the liftoff.) Dubbed the THEMIS mission, which stands for Time History of Events and Macroscale Interactions during Substorms, the objective is to learn more about the physical causes of substorms that create auroras. (Click here to see a NASA movie about the THEMIS mission.) The figure at right shows roughly where the satellites will be positioned within the Earth's magnetosphere. In addition to the five satellites, 20 THEMIS All-Sky cameras are being deployed across Canada and Alaska to simultaneously record images of auroras from the ground. The THEMIS-Canada webpage covers the Ground-Based Observatories research:
THEMIS will consist of five satellites that every four days will come together in a radial alignment over central Canada. When these alignments occur, the satellites will make in situ measurements of the particles and fields that will allow us to identify the region of space in which the substorm energy release starts and consequently the process.
Even a five satellite constellation is not enough to adequately sample the enormous three-dimensional region of space of interest. Fortunately, we can use simultaneous observations of the aurora to identify which events start in the region that is adequately sampled by the satellites. As part of THEMIS, an array of twenty Ground-Based Observatories is being set up from the East coast of Canada to the West coast of Alaska. Each GBO has an all-sky imaging white-light auroral camera, and a magnetometer. The THEMIS ASIs will be creating the best near-global sequences of auroral images ever obtained to date.
You can find archived images of the all-sky imager data at the UC-Berkeley GBO THEMIS website.