TOMOGRAPHIC IMAGING OF THE POLAR-CAP IONOSPHERE OVER SVALBARD

First results are presented from an experiment to image the electron d ensity in the polar-cap ionosphere above Svalbard using tomographic te chniques. The results show localised enhanced densities in the cusp an d throat region, the elevated densities of a polar patch, relatively l ow densities in corotating plasma flux tubes in darkness at lower lati tudes and the depleted densities of the polar hole. The reconstruction of these features, known to occur at polar latitudes, confirms the po tential of tomography for imaging the ionosphere at these very high la titudes. (C) 1997 Elsevier Science Ltd.