Sounding the solar atmosphere: from synoptic telescopes design to gravity waves detection

Understanding and identifying the Space Weather precursors constitute a crucial aspect on solar and stellar physics and for the realization of services to protect human technological assets. Continuous multi-line observations of the Sun can be used to infer the 3D structure of the magnetic field and dynamics of the Sun. Full-disk magnetic and velocity maps of the Sun are fundamental elements to study and forecast Space Weather events, such as flares, coronal mass ejections and solar energetic particles, looking for precursors and descriptors. A better understanding of the physical processes behind these events is possible only by monitoring continuously the Sun. The main driver of these, and other, phenomena is the magnetism of the Sun. The interaction between the solar plasma and magnetic field can be studied according to the laws of magnetohydrodynamics (MHD). These laws consider both the fluid mechanics and Maxwell’s electromagnetism, and its mathematical approach is fundamental in Solar Physics. The solution of MHD equations can be used to study the propagation of waves in the Sun and in its atmosphere or to simulate the solar magneto-convection. We still do not have a full comprehension of the phenomena related to MHD, and therefore to Space Weather precursors; for these reasons, we need new data and tools. The Tor vergata Synoptic Solar Telescope (TSST) is a new robotic and compact facility that will observe continuously the Sun providing three kinds of full-disk maps: chromospheric image (Hα line), photospheric Dopplergram (Ki D1 line) and photospheric magnetogram (Ki D1 line). The same custom channel based on potassium Magneto-Optical Filters (MOF) will acquire Dopplergrams and magnetograms. The characterization of these filters confirms the excellent stability of the passbands, and the custom optical design will provide almost diffraction-limited maps. In this thesis work I faced the problem of solar activity and the precursors of Space Weather events with a dual approach. First I worked on the development of the TSST. I collaborated in the realization of the telescope optics on the optical bench of the Solar Physics Lab in Tor Vergata, I spectrally qualified the MOF filters (in collaboration with the colleagues of the INAF Astronomical Observatory of Naples), I acquired the first light of the TSST and finally I improved and tested a pipeline of data reduction for MOF based telescopes. Second aspect, I analyzed full disk dopplergrams from ground-based telescopes (e.g., MOTH) and high resolution from space instruments (SDO/HMI and SOT/HINODE), to study the complex pattern of acoustic and gravity oscillations present in the solar atmosphere (photosphere and chromosphere). For this purpose, I also developed a 3D numerical model of internal gravity wave propagation. In this thesis, I present the main results obtained during my PhD work on these topics.