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The three-dimensional Magnetic Structure of solar Filaments and Prominences

Final Report Summary - MASFIPRO (The three-dimensional Magnetic Structure of solar Filaments and Prominences)

The determination of the vector magnetic field in solar filaments and prominences (filaments seen against the background sky of the solar limb) is of paramount importance for Solar and Stellar Physics. Solar filaments are one of the most prominent plasma structures that can be seen in our Sun extending from the solar surface and into the hot solar Corona. These structures are embedded in a large magnetic skeleton that provides the means of their support in the solar chromosphere and low corona. Therefore, their magnetic characterization provides an effective way for understanding the magnetic coupling between the Photosphere, Chromosphere, and Corona. More importantly, this characterization is important for Space-Weather forecasting dice these magnetic structures may eventually destabilize and give rise to the ejection of solar filaments that, when the involved energetics are large enough, become Coronal Mass Ejections (CMEs).

The main objectives of this project were to observe solar filaments simultaneously in the Photosphere and in the Chromosphere, to characterize in quantitative detail their magnetic structure, to follow their evolution, and to investigate possible mechanisms behind filament eruptions and generation of CMEs.

During the project, observations of different solar structures in the 1083 nm spectral region have been taken with the GREGOR and VTT (Vacuum Tower Telescope) german telescopes installed at the Izaña Observatory in Tenerife (Spain). The observations have been analyzed with the HAZEL (HAnle and ZEeman Light) inversion code that, from the interpretation of the intensity and polarization signals of the He I 1083 nm triplet spectral line, provide the wanted vector magnetic field information. In particular, during the project it has been possible to:

1- Obtain, for the first time, the variation of the vector magnetic field with height in the so-called solar spicules. This result has a strong impact in the current understanding and modeling of solar spicules and will help understand the physics behind their formation mechanism.

2- Observe a solar filament before it was ejected from the solar surface. The analysis of the spectropolarimetric data and of the Large Amplitude Oscillations the filament exhibits, will help understanding the eruption of this particular solar filament.

3- Obtain data of a quiescent prominence with very high spatial resolution. The data revealed the presence of small-scale structures in intensity and polarization.

4-Detect, for the very first time, a direct spectropolarimetric signature of reconnection jets in the solar atmosphere.