B. Schmieder
Observatoire de Paris, LESIA, 922195 Meudon, France
Solar filaments (or prominences) are magnetic structures in the corona. They can be represented by twisted flux ropes in a bipolar magnetic environment. In such models, the dipped field lines of the flux rope carry the filament material and parasitic polarities in the filament channel are responsible for the existence of the lateral feet of prominences. Any change of magnetic polarities, as for example the cancellation of magnetic flux and decrease of the strength of the magnetic background field, can lead to filament eruptions. A very simple law does exist for the chirality of filaments: commonly dextral/sinistral filaments are in the North/South hemisphere. The chirality is related to magnetic helicity. Such a physical quantity is important for filament formation and eruption leading to CMEs.
After reviewing different observationnal works evidencing these statements, we will focus on some recent 3D MHD simulations of formation and eruption of prominences.