Bochum 2015 – scientific programme

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P: Fachverband Plasmaphysik

P 6: Poster Session - Diagnostics

P 6.7: Poster

Monday, March 2, 2015, 16:30–18:30, Foyer Audimax

Triple-Langmuir-Probes for the diagnostic of high current vacuum arcs and hot gases — •Jan Carstensen, Kristoffer Menzel, Nils Lukat, Markus Abplanalp, Martin Seeger, and Torsten Votteler — ABB Corporate Research, Baden-Daettwil, 5405, Switzerland

The application of Langmuir probes for the diagnostics of high-current arcs or its surrounding is challenging due to a number of reasons, as, e.g., the accompanied high plasma potentials, high thermal loads, and the short time scales involved. Nonetheless, this problem was tackled by a number of works over the last few decades. In a recent paper [1] Mackel et al. gave a detailed description of a triple Langmuir probe setup that is kept under floating conditions, i.e., insensitive to high potentials and that allows to determine electron temperature and the plasma density with µs time resolution. In this contribution, we focus on the applicability of such a triple Langmuir probe to investigate the plasma in the vicinity of a high-current vacuum arc (10kA-30kA) and for the temperature measurement in the exhaust of a hot gas generator driven by a DC arc at normal pressure. Especially in the latter case, we had to modify the approach described in [1] because of the small currents drawn by the probe. It was found that in this case the feed back from the probe circuit must be taken into account and limits the range of applicability.
[1] F. Mackel et al., Contrib. Plasma Phys. 53, 33-38 (2013)