title: Time-resolved spectroscopy of a homogeneous dielectric barrier discharge for soft ionization driven by square wave high voltage.
abstract: Helium capillary dielectric barrier discharge driven by the square wave-shaped high voltage was investigated spatially and temporally by means of optical emission spectroscopy. The finding of the previous investigation conducted with the sinusoidal-like high voltage was confirmed, i.e., the plasma in the jet and the plasma in the capillary constitute two temporally separated events. The plasma in the jet occurs prior to the discharge in the capillary and exists only during the positive half period of the applied high voltage. The time delay of the capillary discharge with respect to the discharge in the jet depended on the high voltage, and it was between 2.4 and 8.4 μs for the voltage amplitude change in the range from 1.96 to 2.31 kV, respectively. It was found that, compared to sinusoidal-like voltage, application of the square wave high voltage results with stronger (~6 times) He line emission in the jet, which makes the latter more favorable for efficient soft ionization. The use of the square wave high voltage enabled comparison of the currents (~1 mA) flowing in the capillary during the positive and negative high voltage periods, which yielded the estimation for the charge dissipated in the atmosphere ((4 ± 20 %) × 10(-11) C) through the plasma jet.
authors: Institute of Physics, Bijenicka 46, 10000, Zagreb, Croatia. blecic@ifs.hr.
authors: Vlasta
authors: V
authors: Horvatic
authors: ISAS-Leibniz Institut für analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, 44139, Dortmund, Germany.
authors: Antje
authors: A
authors: Michels
authors: ISAS-Leibniz Institut für analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, 44139, Dortmund, Germany.
authors: Norman
authors: N
authors: Ahlmann
authors: ISAS-Leibniz Institut für analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, 44139, Dortmund, Germany.
authors: Günter
authors: G
authors: Jestel
authors: Department of Physics, Faculty of Science, University of Zagreb, Bijenicka 32, 10000, Zagreb, Croatia.
authors: Damir
authors: D
authors: Veza
authors: Institute of Physics, Bijenicka 46, 10000, Zagreb, Croatia.
authors: Cedomil
authors: C
authors: Vadla
authors: ISAS-Leibniz Institut für analytische Wissenschaften, Bunsen-Kirchhoff-Str. 11, 44139, Dortmund, Germany.
authors: Joachim
authors: J
authors: Franzke
keywords: Dielectric barrier discharge ionization; Soft ionization; Time-resolved emission spectroscopy