Atmospheric-pressure plasma jets: Effect of gas flow, active species, and snake-like bullet propagation

Abstract

Cold atmospheric-pressure plasma jets have recently attracted enormous interest owing to numerous applications in plasma biology, health care, medicine, and nanotechnology. A dedicated study of the interaction between the upstream and downstream plasma plumes revealed that the active species (electrons, ions, excited OH, metastable Ar, and nitrogen-related species) generated by the upstream plasma plume enhance the propagation of the downstream plasma plume. At gas flows exceeding 2 l/min, the downstream plasma plume is longer than the upstream plasma plume. Detailed plasma diagnostics and discharge species analysis suggest that this effect is due to the electrons and ions that are generated by the upstream plasma and flow into the downstream plume. This in turn leads to the relatively higher electron density in the downstream plasma. Moreover, high-speed photography reveals a highly unusual behavior of the plasma bullets, which propagate in snake-like motions, very differently from the previous reports. This behavior is related to the hydrodynamic instability of the gas flow, which results in non-uniform distributions of long-lifetime active species in the discharge tube and of surface charges on the inner surface of the tube. V C 2013 American Institute of Physics.

Study of Some Electrical Characteristics of the Cylindrical Plasma Jet Using Argon Gas

“…Spike currents are observed in the current waveform in the rising portion of each half cycle of the applied voltage from the start to the time of voltage peaking. The spikes are caused by the filament discharges, which compose the dielectric barrier discharge in air at atmospheric pressure (Bogaerts et al, 2002;Wu et al, 2013). As the two electrodes are of the same size and shape, the discharge current in the positive half-cycle is about the same as that in the negative half-cycle.…”

“…The effects of the gas flow on the propagation of atmospheric pressure plasma plumes within the range of the Ar flow rates from to , was studied (Wu et al, 2013). The length of the downstream plasma plume was found larger compared to the upstream plume.…”

Influence of flowing helium gas on plasma plume formation in atmospheric pressure plasma

“…20,21 The state of gas flow depends on the gas flow velocity and the cross-section of flow channel. The length of the plasma plume is influenced by the state of gas flow, [20][21][22][23][24] and the length increases with increasing the gas flow rate in the laminar flow. 20,21 The length is varied by the applied voltage and the gas flow rate.…”

Highly efficient synthesis of [60]fullerene oxides by plasma jet

“…Because APNPJ generates plasma in open space rather than in confined gaps, there are no restrictions on the size of the objects to be treated, and short lifetime active species and even charged particles can easily reach the employed objects [29–33]. To the best of our knowledge, the application of APNPJ to fullerene chemistry has not been reported until now.…”