Thermal plasmas properties in gas or gas-vapour mixtures

In this contribution we study the validity of mixing rules for several thermal plasma properties (mass density, specific heat at constant pressure, transport coefficients, net emission coefficient) that we have calculated for mixtures of gases and/or vapours: Ar-Fe, Ar-Cu, Ar-H 2 , Ar-N 2 , Ar-O 2 , N 2 -O 2 , SF 6 -N 2 . Some rules are very simple (linearity with proportions) whereas other laws introduce some physical aspects. The results show that the validity of mixing rule is well established for viscosity and emission coefficient, but for the other properties, it depends strongly on the structure of the species and are less valid for molecular plasma than for atomic one.