Dynamics of the photosphere and chromosphere
The motions of the surface plasma of the Sun are a possible source of excitation for the Alfvén waves that, propagating through the chromosphere towards the corona, contribute to the heating of the upper layers of the solar atmosphere via the dissipation of the energy
they carry. In recent years there has also been a gradual re-evaluation of the role of the chromosphere as a fundamental interface region between the photosphere, where surface convection dominates and drives the structure of the magnetic field, and the corona, where the magnetic field determines the structure of the plasma in an essentially "force free" situation. In the field of photospheric and chromospheric studies the community of solar physicists has proposed the construction of the first Italian heliospheric mission (ADAHELI – ADvanced Astronomy for HELIophysics), with the feasibility study financed by ASI and currently awaiting funding for the successive phases. In this area, the ISODY instrument has been proposed, composed of a 40 cm Gregorian telescope and a focalplane suite, including a spectropolarimetric channel for the observation of photospheric and chromospheric lines using a double Fabry-Perot interferometer, a broad-band channel and an image stabilising system.
