Hannover 2016 – scientific programme

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P: Fachverband Plasmaphysik

P 27: Low Temperature Plasmas III

P 27.3: Talk

Friday, March 4, 2016, 11:30–11:45, b305

Simulation of laser photodetachment of negative ions in helium-oxygen barrier discharges and comparison with 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.

The experiment cannot directly provide number densities of negative ions. Therefore, a supporting simulation of the laser photodetachment experiment is necessary. The presented simulation is based on the 1D fluid simulation of a helium-oxygen barrier discharge described in a further contribution. The laser photodetachment is implemented by the interaction between negative ions and a temporally and spatially dependent photon flux. Since the simulation turns out that the intrinsic negative ion density of the simulation is too low to reproduce the laser photodetachment experiment, different modifications and their capabilities of reproducing the experimental results are discussed. The comparison with the experimentally obtained dependencies of the laser photodetachment effect allows conclusions on the spatio-temporal distribution of negative ions.