Solar filaments are large regions of cold and dense plasma structures suspended above the solar surface by magnetic field loops. Usually, they appear long and thin above the chromosphere, but when they project out above the limb of the Sun they are called prominences and appear brighter than their outer surroundings. Filaments can flow for days before disappearing; however, when the magnetic field in their vicinity becomes unstable, they collapse and produce a moving cloud known as a coronal mass ejection (CME). Solar flares and CMEs are one of the most dramatic solar events that can affect the terrestrial environment. The EU-funded project MASFIPRO (The three-dimensional magnetic structure of solar filaments and prominences) was initiated to provide a quantitative description about the magnetic structure and the evolution of solar filaments, and to investigate possible mechanisms behind filament eruptions and CME generation. Scientists collected valuable information through observations of different solar structures in the 1083 nm spectral region. For the first time, they obtained information about the variation of the vector magnetic field with height in the so-called solar spicules. Not only does this help modelling work, it also enhances understanding of the formation mechanism of solar spicules. Another important observation was that of a solar filament before being ejected from the solar surface. Analysis of spectropolarimetric data and of the large amplitude oscillations that the filament exhibited should enhance understanding of the solar filament eruption. High-resolution data of a quiescent prominence revealed the presence of small-scale structures in intensity and polarisation. Lastly, a direct spectropolarimetric signature of reconnection jets was detected in the solar atmosphere for the first time. MASFIPRO provided valuable insight about the eruption and magnetic fields of solar filaments that should further enhance understanding of the magnetic coupling between the solar photosphere, chromosphere and corona.
Solar filaments, space weather, prominences, coronal mass ejection, MASFIPRO