München 2019 – scientific programme
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P: Fachverband Plasmaphysik
P 18: Postersitzung
P 18.42: Poster
Thursday, March 21, 2019, 16:30–18:30, Foyer Audimax
Sub-ns electric field measurements in atmospheric plasma jet — •Nikita Lepikhin, Dirk Luggenhölscher, and Uwe Czarnetzki — Ruhr University Bochum, Faculty of Physics and Astronomy, Experimental Physics V, Germany
This work is dedicated to electric field measurements in a nanosecond pulsed atmospheric plasmas. The discharge is generated by high-voltage (HV) pulses with 6 kV amplitude at a repetition rate of 1 kHz between two electrodes with a length of 20 mm and an inter electrode distance of d=1 mm. The electric field induced Second Harmonic Generation (SHG) is chosen as measurement technique [1]. A Nd-YAG laser with pulse duration of 100 ps is used as a source of radiation at 1064 nm. In the presence of an electric field, second harmonic at 532 nm is generated proportionally to the square of field strength and detected by a PMT. The method works with arbitrary gases, for example, CO2, N2, CH4, Ar and air [1]. Due to the properties of the laser, high temporal (100 ps) and spatial (100 µm) resolution can be achieved. In order to obtain absolute values, calibration with a known field value is necessary. The calibration is made by measuring the second harmonic signal at known DC voltages applied to the electrodes. Test measurements with nanosecond pulses with sub-breakdown voltage amplitude, U, have been performed in ambient air. Good agreement between sub-breakdown electric field values measured by the SHG technique and the field, calculated as U/d, has been obtained. Measurements of the value and the direction of electric field in the discharge are under development. [1] A. Dogariu et. al., Physical Review Applied 7 (2017)