Measurements of high-latitude ionospheric electric fields by means of balloon-borne sensors

Measurements of ionospheric electric fields in the auroral and polar cap regions by means of balloon-borne sensors are described. Launches took place from the Norwegian station of Andenes (Andøya) (69°N, 16°E) during summer 1974. The balloons drifted over the Atlantic to the west coast of Greenland nearly along 69.5°N geographic latitude (within ±1.5°) and were followed by telemetry stations at Andenes, Raufarhøfn (Iceland), and Søndre Strømfjord (Greenland). The electric field data are discussed from the point of view of the two-cell magnetospheric convection pattern which has been established in recent years. Of particular interest are the well-recognized features of the Harang discontinuity as well as electric field data in the vicinity of the polar cusp region.