We have calculated the net emission coefficient of air plasmas at atmospheric pressure in the temperature range between 300 and 40 000 K, in the assumption of local thermodynamic equilibrium and isothermal plasmas. This calculation takes into account the radiation due to the atomic continuum, the molecular continuum, the molecular bands (several systems for O2, N2, NO and N2+) and the atomic lines. Special attention has been devoted in this paper to the description of the molecular bands radiation. The results show that in the high temperature range where molecules are dissociated, the radiation properties of air plasmas are mainly due to those of nitrogen plasmas, the resonance atomic lines playing an important role in spite of their strong self-absorption. At low temperature (T<6000 K) the role of the molecular bands of oxygen (O2) and NO is predominant.

This paper deals with properties of air thermal plasmas containing vapours of iron, silver or copper. The plasma is supposed to be in local thermodynamic equilibrium, for temperatures ranging from 2000 to 30 000 K. First, the equilibrium composition and thermodynamic properties are presented. Then, the radiative properties are calculated using the method of the net emission coefficient. Finally, the viscosity, electrical and thermal conductivities are calculated using the method of Chapman-Enskog. For all mixtures, mole fractions have been used. The results are computed for various values of pressure, plasma size and proportions of vapours. The influence of metallic vapour is important on the electrical conductivity and on the radiation, even at low concentration. All the metallic vapours present a similar behaviour except iron, which has a stronger radiation emission than the other components.