Düsseldorf 2007 – scientific programme

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P: Fachverband Plasmaphysik

P 2: Diagnostische Methoden

P 2.3: Talk

Monday, March 19, 2007, 11:45–12:00, 6C

Laser spectroscopic electric field measurement in krypton — Tobias Kampschulte¹, •Dirk Luggenhölscher¹, Mark Bowden², and Uwe Czarnetzki¹ — ¹Institut für Plasma- und Atomphysik, Ruhr-Universität Bochum, 44780 Bochum — ²Department of Physics and Astronomy, The Open University, Milton Keynes, MK7, 6AA, UK

The electric field in the plasma is a key parameter for the understanding of the structure and dynamic of the sheath, electrons and ions. Once the electric field distribution is known, it is possible to determine voltages, charge densities and currents. Electric fields can be measured directly by Fluorescence-Dip Spectroscopy (FDS). This technique is a combination of two-photon laser induced fluorescence and absorption spectroscopy using the Stark effect of Rydberg-states. It is non-invasive and provides high sensitivity combined with high spatial and temporal resolution. Here the technique is applied for the first time to krypton. Rydberg-states from the autoionizing series up to n = 50 can be excited. Calibration measurements with known electric fields are performed and fields as low as 25 V/cm can be measured. The Stark-splitting has been calculated ab initio. Experimental and theoretical results agree very well. Acknowledgment: this project is supported by SFB 591, GK 1051