A non-thermal atmospheric pressure argon plasma jet for medical applications has been generated using a high-voltage pulse generator and a homemade dielectric barrier discharge (DBD) reactor with a cylindrical configuration. A plasma jet of about 6 cm of length has been created in argon gas at atmospheric pressure with an applied peak to peak voltage and a frequency of 10 kV and 50 kHz, respectively. The length and the shape of the created plasma jet were found to be strongly dependent on the electrode setup and the applied voltage and the signal frequency values. The length of the plasma jet increases when the applied voltage and/or its frequency increase, while the diameter at its end is significantly reduced when the applied signal frequency increases. For an applied voltage of 10 kV, the plasma jet diameter decreases from near 5 mm for a frequency of 10 kHz to less than 1 mm at a frequency of 50 kHz. This obtained size of the plasma jet diameter is very useful when the medical treatment must be processed in a reduced space. 52.50.Dg; 52.70.-m; 52.80.-s

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.

Atmospheric pressure multi-jet plasma devices have long been considered a promising solution for achieving homogeneous and repetitive surface treatments over large areas. Understanding and addressing the interacting jet’s unique behavior is crucial to reach this goal. This paper contributes to this understanding by presenting a helium-fed, alternating current (AC) powered plasma devices. A honeycomb structure featuring six tubes angled toward a central tube, and a triangular structure consisting of three tubes angled toward each other. These devices were tested, along with derivative models. The study examined the characteristics of the resulting plasma jets, focusing on their dependence on the operational settings, the electrodes configuration, the angle of the tubes relative to the electrodes, and the spatial orientation of the devices. Measurements of the plasma jet length were also conducted under various operating conditions. The results show that the proposed designs delivered longer plasma plumes, as a function of gas flow per tube, compared to the reference single-jet. The collection of jets remained closely packed, avoiding both divergence and coupling, with very little dependence on higher flow rates.