The interactions between the Sun and the Earth
The entire solar system is contained within the heliosphere, a bubble of plasma that forms when the solar wind expands into the local interstellar medium. The interaction between the bodies of the solar system and the solar wind can be very different, depending on whether or not the body is magnetised, and whether or not it has an atmosphere. In thecase of the Earth, due to the interaction between the solar wind and the geomagnetic field, the terrestrial magnetosphere is formed. The full understanding of the mechanisms of energy and mass transfer from the solar wind to the magnetosphere, and, more in general, the knowledge of the modes of response of the magnetosphere-ionosphere to the changes of the solar wind are some of the most important frontiers in the physics of the Sun-Earth relation, the reaching of which sees concerted efforts from both the international and Italian scientific communities. Essential to research in this field are: measurements of the electric and magnetic fields, of the distribution functions of charged particles and the flux of energetic neutral atoms (ENA) from space missions such as CLUSTER, Double Star, ACE, Geotail and IMAGE. Also essential are observations of the aurorae from Earth and space, in particular the Italian community is involved in the maintenance of the ITACA2 observatories in the northern hemisphere and in the acquisition of auroral images at the Antarctic Mario Zucchelli station; the measurement of the ionospheric convection in both hemispheres from the international radar network SuperDARN, in which the Italian community also participates; measurements of variationsin the magnetic field at the Earth's surface, in particular with the Italian management of the geomagnetic station at Baia Terranova and Dome C, in Antarctica, and from the magnetometer network, SEGMA, in southern Europe. In recent years, Italian researchers have produced some very interesting results in this field. In the next few years, Italian researchers will continue to be involved in research in these areas. Participation in theSuperDARN project will continue with the management of the Kerguelen radar and the construction of two new radars at the Concordia base in Antarctica. For the study of the global dynamics of the magnetosphere, an instrument for ENA imaging in the terrestrial magnetosphere has been proposed for the ASI mission, ADAHELI.
