Discussion of the validity of binary collision models for electron broadening in plasmas
Résumé
Recent plasma spectroscopic investigations of line profiles indicate that conditions can be obtained where a usual electron collision operator is unable to describe the entire line profile. This situation arises for plasma conditions when the interactions with electrons is a major broadening mechanism and the quasi-static electron, or non-binary, effects are important. As examples we find that this is the case for high-n hydrogen lines over a wide range of electron densities and low-n hydrogen lines at higher electron density. A solution has been proposed for high-n hydrogen lines by using a frequency-dependent electron broadening operator accounting for some overlapping of the impact and the non-binary regimes. The domain of validity of different approaches that attempt to including many-body dynamical and statistical effects will be discussed and compared with numerical simulations.