SMuK 2021 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 5: Poster I
P 5.7: Poster
Dienstag, 31. August 2021, 14:00–16:00, P
Ion flux measurements in an expanding H2 plasma utilizing a Mach probe — •Vinzenz Wolf1, David Rauner1, and Ursel Fantz1,2 — 1AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg — 2Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching
Density gradients and electromagnetic fields in a low pressure plasma lead to a particle flux. In order to determine the orientation and the magnitude of the ion flux, a mach probe can be used, which typically consists of a specifically arranged set of differently orientated contacts with a limited collection angle. Using the ratio of currents measured with two opposed contacts, the ion flux direction and ion velocity (i.e. the Mach number) can be calculated, the latter relying on models for calibration factors. These are used to describe the influence of the plasma parameters on the ion flow towards the probe and are thus valid for a certain set of plasma parameters.
For characterization purposes a four pin mach probe is used in a cylindrical ICP discharge (1 MHz, 2 - 8 Pa, 200 - 800 W), consisting of a quartz glass tube (Ø 9 cm) where a hydrogen plasma is generated and expands into a stainless steel chamber (Ø 32 cm). The ion flux is determined in a two-dimensional section perpendicular to the cylinder axis of the plasma vessel. The influence of a variation of gas pressure and RF power on the ion flux is investigated, as well as plasma drifts induced by applying an external magnetic field in the expansion region.