The Earth's atmosphere is divided into several altitude regions, identified by their temperature structure. These include the troposphere, stratosphere, mesosphere and thermosphere. The region above about 50 km, where the atmosphere is partially ionized, is known as the ionosphere. At high latitudes the ionosphere is strongly influenced by particles and electric fields controlled by the magnetosphere.

Arctic and Antarctic regions are therefore very good places from which to observe the interactions between the solar wind and the magnetosphere, auroral ionosphere and upper atmosphere.

Other phenomena observed in the upper atmosphere, such as waves and tides, originate in the lower thermosphere, mesosphere, stratosphere and troposphere. The high latitude ionosphere is also affected by all these processes as well as by those related to the magnetosphere.

A particularly suitable site was selected for the EISCAT radars, which are located in the auroral zone of Northern Europe to study these processes and their effects on the Earth's environment.