EUV-filaments and their mass loading

It was found recently (Heinzel et al., 2001; Schmieder et al., 2003) that solar filaments observed in EUV lines by SOHO/CDS are much more extended than their Hα counterparts. This was explained by a large difference between the hydrogen Lyman-continuum and Hα opacities. Two different MHD models were suggested to explain the EUV-filament extensions: the model based on parasitic polarities (Aulanier & Schmieder, 2002) and the model with twisted flux tubes (Anzer & Heinzel, 2003). The latter model can explain our recent findings that at least some parts of the EUV-filament extensions are located relatively high in the corona. These heights can be computed using a new spectroscopic model of EUV-filaments. The mass which is loaded into the EUV-filament extensions is then estimated on the basis of non-LTE transfer calculation. The total filament mass is larger than that derived for the Hα filament itself and this may have consequences for the structure and mass loading of CMEs whenever they form from such filaments - this may answer the question how the extended CME structures can form from rather narrow Hα filaments. We summarize the basic properties of EUV-filaments, present their spectroscopic analysis and give some estimates for mass loading. We then discuss possible relations between EUV-filaments and CMEs, in particular the problems of their masses.