Gas-Temperature-Dependent Characteristics of Cryo-Dielectric Barrier Discharge Plasma under Atmospheric Pressure

In the present work, cryo-dielectric barrier discharge (DBD) plasma was generated continuously below room temperature down to liquid nitrogen temperature (296 to 78 K) under atmospheric pressure using parallel indium–tin-oxide (ITO)-coated electrodes. Gas-temperature-dependent optical emission spectroscopy (OES) measurements and discharge pattern observation of cryo-DBD plasma were performed. In the case of helium gas, the discharge mode of cryo-DBD plasma changed from filamentary mode to glow mode as the gas temperature decreased. When introducing a small amount of nitrogen in helium gas, the filamentary discharge mode persisted upon decreasing the gas temperature, although the discharge pattern changed from concentric rings (296 K) to a hexagon-like pattern (78 K).