Mechanism of ultra-fast heating in a non-equilibrium weakly ionized air discharge plasma in high electric fields

Abstract

Observations of a shock wave propagating through a decaying plasma in the afterglow of an impulse high-voltage nanosecond discharge and of a surface dielectric barrier discharge in the nanosecond range were analysed to determine the electron power transferred into heat in air plasmas in high electric fields. It was shown that approximately half of the discharge power can go to heat for a short (∼1 µs at atmospheric pressure) period of time when reduced electric fields are present at approximately 10³ Td. A kinetic model was developed to describe the processes that contribute towards the fast transfer of electron energy into thermal energy under the conditions considered. This model takes into account previously suggested mechanisms to describe observations of fast heating in moderate (∼10² Td) reduced electric fields and also considers the processes that become important in the presence of high electric fields. Calculations based on the developed model agree qualitatively with analyses of high-voltage nanosecond discharge observations.