Two-dimensional modelling of the dielectric barrier discharge in air

A self-consistent two-dimensional modelling of microdischarges in devices in which one of the electrodes is covered with a dielectric is presented. The discharge development can be divided into four phases, a Townsend. an ionization wave or streamer, a cathode layer formation, and a decay phase. While during the Townsend phase the initial field strength distribution is hardly distorted, an ionization wave propagates towards the cathode during the following phase. On the wave reaching the cathode, a cathode layer develops. Its radial extension is determined by the increase of the current. During the decay phase the distributions of, for example, field strength and charge carriers are nearly frozen. The discharge fades because of the slow decrease of the field strength within its column. Energy and temperature distributions of microdischarge channels in air at atmospheric pressure are given.