THEMIS (Time History of Events and Macroscale Interactions during Substorms)


After forty years of intense study, the substorm is only partially understood. The NASA-led THEMIS satellite mission is being launched on February 16, 2006, with the primary objective of identifying the physical mechanism that leads to the explosive release of energy in the substorm. 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.

The THEMIS mission is led by the University of California at Berkeley. The primary Canadian contribution to the THEMIS mission has been to deploy, operate, and retrieve data from the 16 (15 to date) GBOs that are deployed in Canada. THEMIS-Canada is funded by the Canadian Space Agency, is led by the University of Calgary, and involves significant contributions from Athabasca University, the Universities of Alberta, Saskatchewan, and New Brunswick, and Natural Resources Canada. This web page documents Canadian involvement in THEMIS for public outreach and scientific purposes.