Description / Background
The polar ionosphere plays a key role in the Sun-Earth relationship, especially in the coupling between the solar wind, the geomagnetic field and the Earth’s upper atmosphere. Understanding the physical laws governing the formation of the high-latitude ionosphere, its behavior and its thermodynamics is an important issue, especially at a time when space weather is developing. In this logic of efforts, incoherent scattering radars in general, and those of the EISCAT scientific organization in particular, are essential tools. Indeed, they are the only instruments to provide the physical parameters essential to our studies: electronic concentration, electronic and ionic temperatures, ionic velocity between altitudes of the order of 80 and 600 km.
EISCAT has six radars, four in mainland Finland, Norway and Sweden, and two on the arctic island of Spitsbergen. The new EISCAT 3D radar system that will eventually replace the continental radars is under construction.
At IRAP, our scientific objectives with EISCAT focus on the effects in the ionosphere of extreme solar events and geomagnetic field line vibrations (ULF waves). Radars are as often as possible coupled with on-board instrumentation (Cluster and Swarm satellites for example) or other ground-based instruments (optical in particular). Such ground-space coordinated studies lend themselves perfectly to comparison with numerical codes (Transcar, IPIM) developed in the laboratory.
Another major interest of EISCAT: the oldest radars have been probing auroral zones for more than 35 years and thus cover more than 3 solar cycles; this is very interesting for statistical studies and space weather.
Involvement of IRAP
IRAP is the only French institute affiliated to EISCAT. It acts as an interface between the consortium and the French community. IRAP also participated in the definition of the scientific objectives of EISCAT 3D.
At the international level, EISCAT is funded by member states and affiliated institutes such as IRAP. The EISCAT 3D project has been supported by successive European Framework Programmes.