This 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.

中文翻译：

---

等离子蜡烛装置发射的霓虹灯的独特模式和特性

这项研究报告了从新型等离子设备（称为等离子蜡烛）发出的霓虹灯等离子流的特征。该设备发射稳定，宽而长的冷等离子体，其形状类似于闪烁的烛光。霓虹灯等离子蜡烛（Ne-PC）在放电传播和羽状图案方面表现出一些有趣的现象，这在其他喷射设备中并不常见。特别注意气流的动力学，发现它对排放特性和射流形状有重大影响。发现Ne-PC设备中的多孔盘均匀地分布了气流，随后增强了放电开始并形成了均匀的圆锥形射流。而且，施加的电压对流动动力学的影响导致射流的圆锥形转变为叉状。这种现象在氦等离子体蜡烛中没有出现，并且观察到感应电流体动力学（EHD）以及气体的低速度，扩散系数和动量在该现象中起关键作用。光学发射光谱测量提供了有关羽状流模式的机理的见解，并描述了其对生成物种的影响。在较高的施加电压下，观察到氖气排放量显着减少，但是由于周围空气的夹带，产生了更高的RONS。此外，还发现，与传统等离子喷射设备（Ne-CPJ）相比，Ne-PC具有更高的生成RONS的能力，而不是氦蜡烛和氖。