Energetic Electron Precipitation and Neutral Atmosphere Temperature Effects - using ALOMAR and correlated observations

Even after 40 years of studies of the Earth’s magnetosphere and its interaction with the ionosphere, there is still a significant scientific interest in energetic (>10 keV) electron precipitation. This includes better knowledge of the physical parameters that are influenced by the energetic electron precipitation. Energetic electron precipitation has a strong influence on the electron density and the conductivity in the lower ionosphere. Further, electron precipitation causes changes in the chemical compo sition and heating of the upper atmosphere. These are central elements in the new ILWS (International Living With a Star) program as well as the new SCOSTEP programme CAWSES (Climate and Weather of the Sun-Earth System). It is especially important to sur vey how the energetic electron precipitation depends on Solar activity and activity in the magnetosphere, such as CME events, substorms, and geomagnetic storms, and what effects the energetic electrons have on the upper atmosphere during such disturbances . The ALOMAR observatory houses a number of active and passive instruments for studying the dynamics of the polar middle atmosphere. For our purposes, the temperature measurements available from the ALOMAR Na Weber Lidar are most valuable. The TIMED sate llite will be another source of temperature data. From measurements of height profiles of the electron density performed by incoherent scatter radars like EISCAT, the flux of the energetic electron precipitation can be estimated, but only along the line of sight of the radar beam. From the EISCAT radar one can, however, obtain very good height resolution (400 m) and good time resolution (10 s or better). By using a network of riometers measuring the absorption of cosmic radio noise, we can establish a p icture of the distribution of the energetic electron precipitation. The large-scale distribution of the electron precipitation can be obtained for the auroral imagers on POLAR and IMAGE.