Berlin 2005 – wissenschaftliches Programm

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P: Plasmaphysik

P 7: Poster: Niedertemperaturplasmen / Plasmatechnologie 3, Diagnostik 3

P 7.5: Poster

Freitag, 4. März 2005, 16:30–18:30, Poster HU

Investigation of the laser and probe induced disturbances of gas discharge. — •Christian Brandt, Holger Testrich, Ruslan Kozakov, and Christian Wilke — Institut für Physik, EMA Universität Greifswald, Domstraße 10a, 17489 Greifswald

The Langmuir probe is a powerful method for the plasma diagnostics. The drawback of this method is the disturbance of the plasma caused by the presence of the probe. In gas discharges at low pressures (<5 Torr) and small currents (<30 mA) the introduction of the probe causes the deformation of the plasma parameters not only in the vicinity of the probe (Debye or Bohm sheaths) but also on the relatively long-range distances up to 10 cm. Similar effect can be produced by the local laser irradiation of the plasma. This work is devoted to the experimental investigations of both disturbances and their mutual interaction. By means of the laser absorption spectroscopy the density of the excited atoms in the vicinity of the probe is determined. A hydrodynamical model is applied for the estimation of the error of the probe measurements caused by the disturbance.