Düsseldorf 2007 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 16: Poster

P 16.5: Poster

Mittwoch, 21. März 2007, 16:30–18:30, Poster A

Plasma Jet Characterization Using Opto-isolated Double Langmuir Probes — •Gonzalo Avaria^1,2, Marcelo Ruiz¹, Heman Bhuyan¹, Mario Favre¹, and Edmund Wyndham¹ — ¹Pontificia Universidad Caólica de Chile, Departamento de Física, Casilla 306, Santiago 22, Chile — ²Institut für Plasmaforschung, Universität Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart

New Langmuir probe measurements of plasma jets emitted from a Pulsed Capillary Discharge(PCD) are presented. These measurements were performed using a PCD working in a continuous negative pulsing mode at 10 kV(∼ 0.7kA, ∼ 10ns) with frequencies up to 50 Hz. Nitrogen was injected trough the cathode side of the discharge with pressures in the 53 Pa to 133 Pa range. The double Langmuir probes were connected with a differential opto-isolated electronic circuit which allowed fast probe measurements in the several nanosecond ranges. Changing the voltage during pulse operation step by step the voltage-current characteristics was obtained. Evaluation of data allowed a description of the plasma jets in terms of electron temperature (T_e) and ion density (n_i) with spatial and temporal resolution. Characteristic values measured for T_e and n_i are in the ten’s of eV and 10¹³ cm⁻³ ranges, respectively. Preliminary measurements of an ionization front propagating from the capillary end into the surrounding neutral background were also performed. Time integrated visible spectroscopy was used to identify plasma jets components. Based on these measurements, a comprehensive characterization of the PCD plasma jets will be presented.