Modelling of low-pressure surface wave discharges in flowing oxygen: II. Power dissipation and gas heating

Abstract

This paper extends the kinetic and gas dynamic model for low-pressure surface wave discharges in flowing oxygen presented in a previous paper to investigate the mechanisms of power dissipation and of gas heating in the discharge. To this end, the gas thermal balance equation is taken into account and supplements the basic set of equations previously used. A detailed discussion of the various mechanisms contributing to gas heating is provided. From a comparison of the predicted gas temperature distribution along the plasma column with measurements, it is concluded that exothermic reactions at the wall such as reassociation of oxygen atoms and quenching of molecules may contribute appreciably to gas heating. Such heating mechanisms are shown to be essentially nonlocal due to the long residence time of the involved species under the gas flow rates considered here.