In November 1995, observations of the ionospheric F region were made in Scandinavia by means of a tomographic chain extending from the south of Finland to the north of Norway. These observations revealed F region structures which, using optical satellite images and ground-based magnetometer data, are interpreted as manifestations of field-aligned currents in the ionospheric F region electron density. A field-aligned plasma enhancement extending to about 700 km altitude is sometimes seen in connection with an upward current, whereas a larger plasma enhancement with an elevated F layer peak altitude is found to lie close to the region of downward current. (C) 2000 COSPAR. Published by Elsevier Science Ltd.
Nygrén, T., Tereshchenko, E. D., Khudukon, B. Z., Evstafiev, O. V., Lehtinen, M. S., & Markkanen, M. (2000). Manifestations of field-aligned currents in tomographic observations of the ionospheric F region. In Advances in Space Research (Vol. 26, pp. 939–942). https://doi.org/10.1016/S0273-1177(00)00033-8