Automatic Geophysical Observatories

The BAS geospace programmes provide a detailed description both of the neutral and ionised atmosphere in the vicinity of Halley (radius ~300 km with the exception of VLF which may extend to 1,000 km), and its projection along the geomagnetic field. The PACE and SHARE experiments give information (such as ion motion, and hence electric fields) within a much larger area poleward of Halley, into the auroral oval and polar cap. However, these data are insufficient in themselves to resolve some of the major issues concerning the flow of energy through geospace, or to uniquely determine the location of ionospheric signatures of various magnetospheric boundaries under all geophysical conditions. The additional information required includes quantitative estimates of the spatial and temporal variations of electric currents, ionisation and heating rates caused by energetic particle precipitation, and the identification of the polar cap boundary and electromagnetic wave spectra.

Realistically, such data can only be obtained with (relatively simple) instruments deployed at remote, unmanned observatories. Therefore, BAS has built, and started to deploy, a spaced network of automatic geophysical observatories (AGOs) under the field of view of SHARE. Several other nations (e.g. USA and the former Soviet Union) are also planning to deploy unmanned observatories in the interior of Antarctica. The BAS network will form a crucial element in this international effort, being particularly important as it would be geomagnetically conjugate to excellent geospace observatory facilities in North America and Greenland.

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