Düsseldorf 2007 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 22: Poster

P 22.17: Poster

Donnerstag, 22. März 2007, 16:30–18:30, Poster A

Time-resolved diagnostics for the examination of mode transitions in inductive discharges — •Philipp Kempkes, Jan Tenfelde, Malte Kischkel, Victor Gorshelev, and Henning Soltwisch — Institut für Experimentalphysik V, Ruhr-Universität Bochum, Bochum, Germany

The long-term aim of this work is to gain additional control over the electron energy distribution function (EEDF) by fast periodic switching between the two operational modes of inductively coupled plasmas (E mode and H mode) by means of amplitude modulation of the input power. A first characterization of the discharge system under power modulation revealed several unreported effects, such as two-stepped processes and the skipping of mode jumps [1], [2]. These results show that the E to H mode transition in inductive discharges is not fully understood yet. In order to obtain a deeper insight into the underlying physics, the electron parameters (e.g. EEDF) under power modulation at higher modulation frequencies (∼ kHz) are investigated. Furthermore the applicability of periodic mode switching for EEDF manipulation is examined. To this end several diagnostic techniques are currently under development or improvement: a nested-cavity far-infrared interferometer, a Thomson scattering system and the utilization of coherent averaging for Langmuir probe measurements.

[1] P. Kempkes, S. V. Singh, C. Pargmann and H. Soltwisch 2006 Plasma Sources Sci. Technol. 15 378–83

[2] S. V. Singh, P. Kempkes and H. Soltwisch 2006 Appl. Phys. Lett. 89 161501-1–3