Hannover 2016 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 20: Poster Session- Low Temperature Plasmas

P 20.17: Poster

Mittwoch, 2. März 2016, 16:30–19:00, Empore Lichthof

1D fluid simulation of helium-oxygen barrier discharges and adaption to the experiment — •Sebastian Nemschokmichal, Robert Tschiersch, and Jürgen Meichsner — Institute of Physics, University of Greifswald

Helium-oxygen discharges at atmospheric pressure are well established in applications because of their ability to produce oxygen radicals under low power consumption. The use of oxygen in a discharge always causes the formation of negative ions, but the influence of negative ions on barrier discharges is poorly investigated. Therefore, we set up a helium oxygen barrier discharge to prove negative ions in a laser photodetachment experiment.

Supplementary, a 1D fluid simulation is developed for comparison. Exemplarily, simulation results are presented and discussed for a pressure of 500 mbar, an admixture of 400 ppm oxygen to helium, and a gap width of 3 mm. In order to enable the comparison with laser photodetachment experiments, the simulation is adapted to the experimentally observed discharge current and gap voltage by varying gas temperature, flux of thermally desorpted electrons and secondary electron emission coefficients. Afterwards, the discharge is characterized by evaluation of most important elementary collision processes as well as the dynamics of charged species. Particularly, the negative ions are characterized by their spatio-temporal distribution in the gap and their production and loss processes. Furthermore, simulations with and without negative ions are compared to point out the importance of negative ions for the simulated discharge.