We present calculated values of transport properties (viscosity, thermal and electrical conductivities) of argon, copper and argon-copper thermal plasmas at equilibrium and non-equilibrium. In addition, combined ordinary and thermal diffusion coefficients, as defined by Murphy, are also given. The calculations are performed in the temperature range 300-25 000 K and at atmospheric pressure.For all these calculations, we use a recent theory developed by Rat to determine the transport properties like, for example, viscosity or combined diffusion coefficients in non-equilibrium plasma (note that equilibrium is only a specific case). We also take great care in evaluating the collision integrals necessary to calculate the transport coefficients (especially the Cu-X interactions). At equilibrium, our results are compared with published values obtained theoretically and experimentally. Moreover, to our knowledge, there are no accessible data for these non-equilibrium argon-copper plasmas.

The interaction between a metallic plasma produced by laser ablation and an ambient gas (argon, air and nitrogen) at atmospheric pressure is studied. The experimental results are compared with theoretical ones given by numerical simulation. Aluminium and copper targets are used. The uniform repartition of iron impurities included in the target (1.6% for Al and 2% for Cu) is warranted by the manufacturer. The Nd : YAG laser delivers pulses of 8 ns FWHM duration with an energy ranging from 70 to 100 mJ at a rate of 10 Hz. The temperature measurements have been performed by the Boltzmann diagram method using iron lines. The influence of ambient gas and target material is studied. After an Abel transform, we observe a maximum of the line intensities off the plasma axis. This shows the formation of gas plasma around the metallic one before complete diffusion of the ambient gas in the metallic plasma. The hydrodynamic model built in one dimension uses the continuity equations. This code is based on the control volume method of Patankar. A temperature and mass fraction profiles are needed as initial conditions. This model is able to describe the temporal evolution of the temperature and of the diffusion in the plasma. It allows us to study the mixture of the metallic plasma and the ambient gas as soon as the plasma is thermalized and local thermodynamic equilibrium is established. There is good agreement between the results of the simulation and the experimental results.

Several microwave driven plasma torches are being developed at PSI for a variety of applications. The plasma in the torches is confined by a vortex flow. thereby eliminating the need for confining dielectric tubes. This allows the use of very high power discharges with very reactive gases such as oxygen and fluorine. Temperatures from less than 1000 C to over 4000 C can be achieved, resulting in the efficient dissociation of a number of useful gases. Gases tested to date include air, oxygen, nitrogen, SF6, steam as well as others. Torches operating with 30 kW @ 915 MHz and 5 kW @ 2450 MHz will be described.Measurements of the operating parameters, including the enthalpy and gas species content, will be presented and compared to results of simulations. References:Pliysit~ul Sciences h c . 'Laser Induced Breakdown Spectroscopy (LIBS) is a powerful method for direct measurement of element concentration in all material analysis and metallurgical applications. This technique consists on the measurement of the emission line intensity of the different species in the plasma produced near the surface by study is devoted to a numerical simulation of the expansion of the metallic plasma (copper) in the ambiant gas (nitrogen or argon) at atmospheric pressure, and to a comparison with experimental results. Numerical modelling. The hydrodynamic model established in a I D configuration uses the continuity equations. The code is based on the control volume method of Patankar. The calculation starts after thermalisation of the copper vapour plasma. The initial conditions assume the knowledge of temperature and mass fraction profiles. A parametric study allowed us to know the influence of this initial conditions on the plasma decay. After calculation of the mass density and of the transport coefficients in function of the plasma composition and of the temperature, the model allows us to calculate the plasma parameters (temperature evolution, expansion speed, mass fraction evolution, cooling velocity, radiation, thermal diffusion and convection). Experiments. We used a Nd :YAG laser (1064nm, 120 mJ), a fiber cable and a spectrometer in conjunction with a gated optical multi-channel analyzer for the analysis of the emission lines. This system allowed both spatially and temporally resolved spectra to be recorded. The metallic plasma parameters are obtained by recording spectral lines of iron contained in the copper.