Plasma diagnostics and numerical simulations: insight into the heart of analytical glow discharges

This review paper gives an overview of the fundamental studies, both by plasma diagnostics and numerical modelling, that have been carried out for analytical glow discharges. After some introduction about the basic aspects of a glow discharge, the various plasma diagnostic techniques that have been described in the literature for analytical glow discharges will be outlined, including a discussion on their strong and weak points, and a presentation of some characteristic results. The major part of the paper, however, focuses on modelling activities for a better description of glow discharges. An overview is given of possible modelling approaches for glow discharges in general, as a means to point out why we have chosen to describe analytical glow discharges by a hybrid modelling network, consisting of various sub-models. The latter will be briefly described, and typical calculation results will be outlined, mainly for glow discharges in direct current (dc) mode, which are nowadays well described by numerical modelling. The modelling of radiofrequency (rf) glow discharges was found to be more complicated, as described in this review, but we believe that the most important aspects of the rf glow discharge are also correctly predicted. For pulsed discharges, on the other hand, some unanswered questions remain, mainly related to the so-called afterpeak behaviour. Hence, this will need further attention in the future, by modelling and/or plasma diagnostic measurements.