Combined rocket and ground observations of electron heating in the ionospheric F-layer

Results from the combined ionospheric sounding rocket and incoherent scatter radar experiment NEED (Non-Maxwellian Electron Energy Distribution) are presented. It is shown that the in-situ measurements of the electron temperature yielded much higher values than the corresponding measurements obtained from the ground. A significant suprathermal electron population was also detected in the F-layer. It is suggested that these two observations are strongly related to each other. It is also shown that the suprathermal electron population was strongly field-aligned, and that the production region was above the rocket trajectory. This interaction was very likely to have been initiated by the auroral particle precipitation present during the whole experiment.