On the Stability and Turbulences of Atmospheric-Pressure Plasma Jet Extracted From the Exit of a Long Flexible PVC Tube

Atmospheric-pressure plasma jet (APPJ) created in helium was extracted far from its electrical discharge ignition using a conductor wire inside a flexible plastic tube. The effects of the geometrical parameters of the setup, helium flow, and the applied discharge voltage on the extracted plasma jet characteristics were investigated. It appears that increasing voltage and/or gas flow leads to the augmentation of the jet length. However, in certain combinations, turbulences of the plasma plume may occur. The turbulences threshold may be shifted by changing voltage or tube diameter. Moreover, increasing the tube and wire length induces more dielectric losses along the tube and adds extra impedance to the reactor leading to jet length retraction.