Bochum 2015 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

P: Fachverband Plasmaphysik

P 21: Theory and Modelling II

P 21.5: Vortrag

Mittwoch, 4. März 2015, 15:25–15:40, HZO 50

Determination of ion mobilities from the ion energy distribution functions — •Tsanko Vaskov Tsankov and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44780 Germany

The ion mobilities or, equivalently, the ion-neutral collision frequencies are important input parameters not only for numerical simulations but also for the general understanding of the discharge structure and the ionisation balance. Due to the complex internal structure of both collision partners, the theoretical calculation of the collision characteristics is in this case a cumbersome task and most of the available data comes from drift tube experiments [1]. The ion mobilities in a foreign gas are difficult to obtain even experimentally and such data are scarce.

Here a relation between the ion energy distribution functions at the wall of an inductive discharge and the plasma parameter profiles is derived which allows the determination of ion-neutral collision frequencies. The technique works equally well for ion collisions with the parent gas or with foreign species. Values for several noble gases and their mixtures are obtained and compared with available literature data [1].

[1] E W McDaniel, E A Mason, The Mobility and Diffusion of Ions in Gases (John Wiley & Sons, New York, 1973)