Temperature-dependent transition of discharge pattern of He/air cryoplasma

Dielectric barrier discharges were generated under atmospheric pressure at temperatures ranging from room temperature down to 88 K. The gas temperature of the plasma generated by the discharges was controlled by liquid nitrogen, and a mixture of helium and air was used as the discharge gas. We found that microdischarges exhibited temperature-dependent specific discharge patterns as the temperature decreased. This transition of discharge patterns was closely related to the change in the gap voltage at breakdown. A possible scenario that may explain the pattern of the transition of the microdischarges is discussed. (C) 2008 American Institute of Physics.