In this paper, atmospheric pressure air discharge plasma in quartz tube is excited by 15 ns high-voltage nanosecond pulsed discharge (HVNPD) and sinusoidal alternating current discharge (SACD), respectively, and a comparison study of these two kinds of discharges is made through visual imaging, electrical characterization, optical detection of active species, and plasma gas temperature. The peak voltage of the power supplies is kept at 16 kV while the pulse repetition rate of nanosecond pulse power supply is 100 Hz, and the frequency of sinusoidal power supply is 10 kHz. Results show that the HVNPD is uniform while the SACD presents filamentary mode. For exciting the same cycles of discharge, the average energy consumption in HVNPD is about 1/13 of the SACD. However, the chemical active species generated by the HVNPD is about 2–9 times than that excited by the SACD. Meanwhile, the rotational and vibrational temperatures have been obtained via fitting the simulated spectrum of N2 (C3Πu → B3Πg, 0-2) with the measured one, and the results show that the plasma gas temperature in the HVNPD remains close to room temperature whereas the plasma gas temperature in the SACD is about 200 K higher than that in HVNPD in the initial phase and continually increases as discharge exposure time goes on.

Electrical and optical characteristics of diffuse nanosecond pulsed discharge plasma using a needle-array electrode in atmospheric air Effects of pulse polarity on nanosecond pulse driven dielectric barrier discharge plasma actuators J. Appl. Phys. 115, 043306 (2014); 10.1063/1.4863175The effect of dielectric thickness on diffuse nanosecond dielectric barrier discharges using a needle array-plate electrode configuration in air at atmospheric pressure In this paper, positive, negative, and bipolar nanosecond pulses are employed to generate stable and diffuse discharge plasma using array needles-plate electrode configuration at atmospheric pressure. A comparison study of discharge images, electrical characteristics, optical emission spectra, and plasma vibrational temperature and rotational temperatures in three pulsed polarity discharges is carried on under different discharge conditions. It is found that bipolar pulse is beneficial to the excitation of diffuse dielectric barrier discharge, which can generate a room temperature plasma with more homogeneous and higher discharge intensity compared with unipolar discharges. Under the condition of 6 mm electrode gap distance, 26 kV pulse peak voltage, and 150 Hz pulse repetition rate, the emission intensity of N 2 (C 3 P u ! B 3 P g ) of the bipolar pulsed discharge is 4 times higher than the unipolar discharge (both positive and negative), while the plasma gas temperature is kept at 300 K, which is about 10-20 K lower than the unipolar discharge plasma. V C 2014 AIP Publishing LLC. [http://dx.

In this paper, we present a large area nanosecond pulse gas‐liquid diffuse discharge plasma with small flow rate of helium as working gas. The discharge images, the waveforms of pulse voltage & current, the emission spectra, and the gas temperature are measured or calculated. As a energy‐efficient sterilization for sewage, the efficiency of sewage sterilization in both static liquid and flowed liquid are investigated. It is found that an optimal value of helium gas flow rate in the production of reactive oxygen species (OH, O) can be obtained when the He flow rate is 5 ml min−1, under this condition, high inactivation efficiencies of bacteria and fungus can be presented.

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