Optical and electrical diagnostics on a long atmospheric pressure cold plasma plume

Summary form only given. Atmospheric pressure non-equilibrium plasmas , which have electron temperature much higher than gas temperature, are attracting lots of attentions recently. The high electron temperature is favorable for enhancing the plasma chemistry and the low gas temperature makes them suitable for applications where gas temperature close to or at room temperature is required. In this paper, a special designed room temperature plasma jet device is reported. The device is capable of generating a helium plasma plume up to 11 cm long in the surrounding air. Firstly, the I-V characteristics of the device driven by both AC and pulsed DC power supply are studied and compared. Secondly, the rotational, vibrational and electron exciting temperatures of the plasma plume are studied. Thirdly, the spatial and temporal emission behaviors of the plasma plume are investigated for both driven mode. Finally, the safety of the device is evaluated by a simple electrical model, when a human is contacting with the plasma plume, it is concluded that the potential drop on the human is much less than 66 V for the applied voltage of 5 kV.