Physics on plasma chemistry

In this paper, after a brief historical review of plasma chemistry, a short description of the different types of plasmas used, and of their means of production, we will present the plasma chemistry reactor with the problems of mixing the reactants with the plasma, the quenching and the catalysis. This is followed by a discussion of diagnostic techniques either on the plasma itself : spectroscopic measurement of temperature and population, laser fluorescence spectroscopy, gas velocity measurements and mass spectroscopy of ions ; or on the condensed materials injected into the plasma : velocity, surface temperature, population and diameters of the particles. For the reactions in homogeneous phase a brief summary on equilibrium and kinetics calculations is followed by an illustration of the application of this calculations with three examples : NO synthesis in a DC plasma jet, C2H2 and HCN synthesis in a HF plasma torch, organic compound synthesis with the O2 1 Δg metastable state produced in a HF low pressure plasma. For the reactions in heterogeneous phase, first we recall thermodynamic and transport properties of the plasma and then we deal with heat and mass transfer plasma particles. The applications described are first concerned with physical changes of solid materials in plasma : plasma spraying, spheroidisation, vaporisation, condensation and second chemical reactions.