Hannover 2020 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 2: Atmospheric-pressure plasma and applications 1

P 2.4: Vortrag

Montag, 9. März 2020, 12:00–12:15, b305

Electric field measurements in ns-APPJ with sub-ns time resolution — •Nikita Lepikhin, Dirk Luggenhölscher, and Uwe Czarnetzki — Institute for Plasma and Atomic Physics, Ruhr University Bochum, D-44780 Bochum, Germany

The work is dedicated to electric field, E, measurements in a nanosecond pulsed atmospheric pressure plasma. Due to a high reduced electric field, E/N, providing efficient excitation of the electronic states of atoms or molecules, nanosecond discharges are widely used as a source of non-thermal reactive plasmas in a variety of applications: surface treatment, plasma medicine, plasma flow control, plasma assisted ignition and combustion. The reduced electric field is the key information for plasma kinetic studies. Known temporal profiles of E/N in the discharge allow to determine the electron energy distribution function evolution and, consequently, the discharge development. Experimentally measured E/N profile accompanied by electric current measurements can be used as a benchmark to verify plasma kinetic models. In this work, the electric field in a ns-discharge in a He:N₂ mixture is studied with sub-ns time resolution. Electric-Field Induced Second Harmonic generation (E-FISH) is used as a measurement technique [A. Dogariu et. al., Phys. Rev. Appl. 7 (2017)]. A laser beam is focused into the discharge gap and in the presence of an electric field a coherent signal beam at the second harmonic of the laser frequency is generated. The method is non-resonant and can be used for any gases. The technique provides the absolute value of the electric field as well as its direction. High temporal and spatial resolutions are achieved.