Experimental Investigation on Transition Conditions of Discharge Modes in Atmospheric Pressure Two-Dimensional Jet Array in He

For obtaining jet plasma with high strength and large area, two distinct modes of two-dimensional plasma jet array discharge at atmospheric pressure in He are generated with honeycomb like electrode arrangements. The discharge characteristics of the two modes array are studied and compared. The influence of the parameters such as the gas flow rate, distance between the jet units and voltage amplitude on mode transition of the jet array is studied. Results show that the jet arrays in He appear two modes, one is intense-coupling mode with high discharge strength and the other is even mode with relative large discharge area. At the same applied voltage amplitude, the discharge power, transmission charge and intensity of the main particle lines in the former mode are higher than those in the latter mode. The distance among the jet units and the gas flow rate are the main factors affecting mode transition of the jet array, while the change in voltage amplitude only affect discharge strength of the jet arrays without affecting mode transition. The discharge is in intense-coupling mode when the distance among the jet units is 0.2mm and the gas flow rate is less than 5L/min, and it will transit to even mode when the gas flow rate is larger than 5L/min. When the distance among the jet units is greater than 0.4mm, the discharge is only in even mode no matter what changes of the applied voltage or gas flow rate.