Characteristics of Atmospheric Microplasma in Small Discharge Gaps

Emission spectroscopy analysis and imaging technique were used to study the microplasma phenomena. The microplasma discharge in Ar and N2/Ar was analyzed along the discharge gap area and also for specific periods of time during the discharge. Microplasma showed characteristics specific with an atmospheric glow discharge: positive column, Faraday dark space and negative glow. Spatial and temporal distribution showed the propagation of light emission from anode towards cathode. The light emission was measured up to 365 ns as long as the discharge current was measured. The intensity of N2 Second Positive Band System (N2 SPS) peak at 337.1 nm was measured along the discharge gap and at various time intervals during the discharge using an effective shutter opening time of high-speed ICCD camera of 3 ns. The peak of Ar I at 696.5 nm was used to estimate the value of electron density using Stark broadening method. The calculated value of electron density ne=1.338x10 15 /cm 3 is specific for atmospheric pressure nonthermal plasmas.