Observations of auroral electrons with sounding rockets and the Geos-2 geostationary satellite

Kiruna Geophysical Institute has participated with auroral particle experiments in several Swedish sounding rocket payloads launched from Esrange. Three of these campaigns took place when the geostationary satellite GEOS-2 was located on a field line with the foot-point in northern Scandinavia. The sounding rockets have been launched during different auroral conditions. The angular and energy distribution and other parameters of the observed plasma population (e.g. density and characteristic energy) are used to give information about the sources of auroral particles and possible acceleration mechanisms. It is found that many properties of the electron distribution above pre-midnight auroral structures can be explained by acceleration of a low temperature electron population of boundary layer origin through a quasi-steady electric field parallel to the magnetic field lines. Electron data at low latitude are compared with GEOS-2 data during an auroral pulsation event