The project ALEOS, supported by the Romanian Space Agency (ROSA) under the STAR programme, concentrates on ionospheric electrodynamics, with emphasis on the auroral region - where the magnetic field lines provide a direct connection between the collisional ionosphere-thermosphere and the collisionless magnetosphere. The multi-point measurements of Swarm, conjugate at times with ground data, make possible for the first time a systematic examination of the ionospheric current closure associated with aurora.

The Swarm mission provides high resolution multi-point data from the low altitude end of the magnetosphere-ionosphere-thermosphere (M-I-T) system, complementary to data obtained by the ESA Cluster mission near the topside auroral acceleration region (AAR) and by the NASA THEMIS mission in the inner plasma sheet. With Swarm, multi-point in-situ data are available from all the key regions of the auroral current circuit, namely the generator region (probed by THEMIS), the AAR (probed by Cluster), and the resistive I-T (probed by Swarm and ground based observatories).

ALEOS is executed by the Space Plasma and Magnetometry Group (GPSM) at the Institute for Space Sciences (ISS), Bucharest-Magurele. ALEOS takes advantage from the data validation work carried on under the VALS project and benefits from the international collaborations of GPSM.

Left: Artist view of the Swarm satellites. Middle: Swarm constellation in orbit, with two spacecraft side by side, at 460 km altitude, and the third satellite in a higher orbit, at 530 km altitude. Credit: ESA. Right: Sketch of the Swarm, Cluster, and THEMIS spacecraft, probing key regions of the auroral current circuit. After Marghitu (2012).