Distinctive patterns and characteristics of neon jet launched from plasma candle device

Abstract

AbstractThis study reported the characterization of neon plasma jets emerging from a novel plasma device known as a plasma candle. The device launches stable, wide, and long cold plasmas in a shape resembling a flickering candle flame. The neon plasma candle (Ne‐PC) exhibited several interesting phenomena in terms of the discharge propagation and plume pattern, which are not common in other jet devices. A particular attention was paid to the dynamics of the gas flow, which was found to have significant effects on the discharge characteristics and jet shape. It is found that a porous disc in the Ne‐PC device distributed the gas flow uniformly, and subsequently enhanced the discharge initiation and formed a uniform conical jet. Moreover, the effect of the applied voltage on the flow dynamics led to a transformation in the conical shape of the jet to a fork‐like shape. This phenomenon did not appear in the helium plasma candle, and it is observed that the induced electrohydrodynamic (EHD) as well as the low velocity, diffusion coefficient, and momentum of the gas play a crucial role in this phenomenon. Optical emission spectroscopy measurements provided insights into the mechanism of the plume pattern and described its effect on the generated species. At higher applied voltages, a significant reduction in neon emissions was observed, but higher RONS were generated, due to the entrainment of the surrounding air. Furthermore, it is found that the Ne‐PC has a higher ability to generate RONS than the helium candle and neon in the conventional plasma jet devices (Ne‐CPJ), thereby suggesting its feasibility for material processing and biomedical applications.