Begell House Inc.
High Temperature Material Processes: An International Quarterly of High-Technology Plasma Processes
HTM
1093-3611
7
1
2003
A STATISTICAL SURVEY TO THE FLUCTUATIONS OF ELECTRIC ARCS
10
10.1615/HighTempMatProc.v7.i1.10
Olivier
Vallee
LASEP (Laboratoire d'Analyse Spectroscopique et d'Energetique des Plasmas), UFR-Faculte des Sciences, Antenne de BOURGES, Universite d'ORLEANS, rue Gaston Berger, BP 4043, 18028 BOURGES CEDEX, FRANCE
Eric
Moreau
LASEP, Faculte des Sciences, Université d'Orléans, rue Gaston Berger BP 4043, 18028 Bourges Cedex; Department of Fluids, Thermique et Combustion Institut PPRIME (CNRS UPR3346, Universite de Poitiers, ISAE-ENSMA) Bd Marie & Pierre Curie
The purpose of the present paper is a first attempt to the modeling of electric arcs as an alternative method to numerical simulations. We base our approach on two aspects of statistical physics: random walk and Markovian processes. The first approach uses basic concepts of polymer physics to determine a typical length of an arc. The Markovian approach leads to consider an arc as the consequence of the charged particle trajectories composing the plasma, and then to determine an estimate of the arc radius. Correspondences between this statistical survey to fluctuations in electric arcs and the macroscopic studies are also evoked.
THE EFFECT OF DIFFERENT REGIMES OF OPERATION ON PARAMETERS OF A WATER-VORTEX STABILIZED ELECTRIC ARC
6
10.1615/HighTempMatProc.v7.i1.20
Jiri
Jenista
Institute of Plasma Physics ASCR, Za Slovankou 3, 182 21 Prague
The aim of the present paper is to make conclusions about behaviour of the water-vortex stabilized plasma torch under different regimes of operation and radiation models involved. For this purpose we calculated steady states of such arc for the currents 300-600 A assuming two different radiation models, and several radial positions of the phase transition between water and vapour in the discharge chamber which cannot be measured in experiments. Deviations from local thermodynamic equilibrium (LTE) within the arc column are estimated due to the criteria for kinetic equilibrium and space temperature gradients.
SPECTROSCOPIC STUDY OF A THERMAL PLASMA JET GENERATED BY A HYBRID WATER-ARGON STABILIZED DC ARC TORCH
6
10.1615/HighTempMatProc.v7.i1.30
V.
Sember
Institute of Plasma Physics, AS CR, Za Slovankou 3, P.O. Box 17, 182 21 Prague, Czech Republic
Methods of optical emission spectroscopy (OES) are used to determine basic parameters of the plasma jet such as temperature, electron number density, and mole fractions of plasma components. The analysis is based on the measurement of a large variety of argon, oxygen and hydrogen spectral lines in the whole visible spectral region for various operating conditions. The electron number density is determined from a profile of Hb line. The temperature is obtained from Boltzmann diagrams and from the ratio of atomic and ionic lines. A discrepancy is found in evaluation of the excitation temperature from certain argon ionic lines. The mole fraction of oxygen significantly decreases towards the jet centerline. This effect increases with increasing temperature gradient, and is explained mainly as a result of inhomogeneous mixing of argon and water in the stabilizing channel of the torch.
DETERMINATION OF FLOW VELOCITY FROM ANALYSIS OF HYDRODYNAMIC OSCILLATIONS OF THERMAL PLASMA JET
6
10.1615/HighTempMatProc.v7.i1.40
Vladimir
Kopecky
Thermal Plasma Department, Institute of Plasma Physics AS CR, Za Slovankou 3, 18200, Praha 8, Czech Republic
Milan
Hrabovsky
Institute of Plasma Physics, Academy of Sciences Za Slovankou 3, 182 00, Prague
The coherent oscillations with frequency in the range 20 to 100 kHz are initiated close to the nozzle exit in plasma jet generated by torch with external anode. Frequency and phase velocity of the oscillations were determined experimentally for various diameters of exit nozzle and various plasma compositions. The plasma flow velocity was evaluated from the speed of propagation of shock waves that were initiated by anode breakdowns in a restrike mode of anode attachment. The relation between characteristics of hydrodynamic oscillations and plasma flow velocity were expressed by simple formulae for various flow rates and diameters of exit nozzle. Measured characteristics of the oscillations were than used for determination of plasma velocity. The fluctuations of flow velocity due to ripple of rectified current were determined by this method.
ON THE EFFECT OF ARC CURRENT, ARC VELOCITY AND ELECTRODE TEMPERATURE ON COLD ELECTRODE EROSION
8
10.1615/HighTempMatProc.v7.i1.50
A.
Marotta
Institute of Physics, University of Campinas, UNICAMP, SP, Brazil
L. I.
Sharakhovsky
Instituto de Fisica "Gleb Wataghin", Universidade Estadual de Campinas, Unicamp, 13083-970, Campinas, Sao Paulo, Brazil; The Luikov Heat & Mass Transfer Institute, P. Brovki street, 15, 220072, Minsk, Republic of Belarus
A. M.
Essiptchouk
Instituto de Fisica "Gleb Wataghin", Universidade Estadual de Campinas, Unicamp, 13083-970, Campinas, Sao Paulo, Brazil; The Luikov Heat & Mass Transfer Institute, P. Brovki street, 15, 220072, Minsk, Republic of Belarus
Results of experimental investigation of copper cathode erosion in magnetically driven arc versus arc current, arc velocity and electrode surface temperature are presented. The experiments showed the presence of two different erosion regimes as function of current and temperature. First, erosion slowly grows for low values of these parameters, then, a sudden increase of erosion occurs. A critical temperature of about 500-600 К for this transition was found for magnetic fields in the range 0.01-0.35 Т. We observed that, besides the decrease of erosion for low arc velocities, erosion can also increase for high velocities, contrary to what was expected. A reasonable agreement to predictions of a previously published erosion model is obtained.
CRITERION FOR TRANSITION FROM LAMINAR TO TURBULENT FLOWS OF ARGON IN PLASMATRONS
6
10.1615/HighTempMatProc.v7.i1.60
Oleg A.
Sinkevich
Science Technological Center of Associated Institute for High Temperature, Russian Academy of Science and Moscow Power Engineering Institute (Technical University), Russia
S. E.
Chikunov
Science Technological Center of Associated Institute for High Temperature, Russian Academy of Science and Moscow Power Engineering Institute (Technical University)
Vasilii V.
Glazkov
Moscow Power Engineering Institute (Technical University), Russia
E. Kh.
Isakaev
Science and Engineering Center for Energy-Efficient Processes and Equipment of Joint, Institute for High Temperatures of Russian Academy of Sciences Izhorskaya 13/19, Moscow, 127412, Russia
Numerical simulations of the fully developed flow region in a cylindrical channel of the plasmatron are performed. As the results, temperature and velocity radial distributions, dependences of pressure and voltage gradients on operating parameters of the plasma torch are obtained for the argon arc burning in the laminar gas flow. Special attention was given to define and to calculate criteria for transition from the laminar to the turbulent regime of the gas flow in the fully developed flow region. For this purpose some experimental results of Frind, Damsky [2] and Runstadler [1] were employed. Using these experimental results we have calculated the value of the critical Reynolds number characterizing the onset of the turbulence for the arc flow.
ON-LINE TEMPERATURE MEASUREMENT IN A PLASMA REACTOR FOR FULLERENE SYNTHESIS
8
10.1615/HighTempMatProc.v7.i1.70
Stephane
Abanades
Laboratoire Procédés Matériaux et Energie Solaire (CNRS-PROMES), 7 Rue du Four Solaire, Odeillo, 66120 Font-Romeu, France
J. M.
Badie
C. N. R. S., Institut de Science et de Genie des Materiaux et Procedes B. P. 5, Odeillo, F-66125 Font-Romeu Cedex
Gilles
Flamant
CNRS PROMES UPR 8521, Tecnosud, Rambla de la Thermodynamique, 66100 Perpignan, France
L.
Fulcheri
Centre D'Energetique, Ecole Des Mines De Paris; Rue Claude Daunesse, B. P. 207, F-06904 Sophia Antipolis Cedex
J. Gonzales
Aguilar
Center for Energy and Processes, Ecole des Mines de Paris, Rue Claude Daunesse B.P.. 207, F-06904 Sophia-Antipolis Cedex, France ; Dpto. De Fisica Aplicada, Universidad de Cantabria, Av. Los Castros s/n, 39005 Santander, SPAIN
T. M.
Gruenberger
Ecole des Mines de Paris, B.P. 207, P-06904 Sophia Antipolis, France
Frederic
Fabry
C. N. R. S., Institut de Science et de Genie des Materiaux et Procedes B. P. 5, Odeillo, F-66125 Font-Romeu Cedex
Vaporization of carbon particles injected in a plasma flow is an alternative to existing processes for mass production of fullerenes. In order to obtain a large fullerene-soot production the residence time of particle at temperature larger than the vaporization temperature must be large enough. This critical point was checked in the pilot reactor by OES.
The helium plasma was generated inside a carbon nozzle by a 3-phase AC plasma source using graphite electrodes. The plasma flow was then cooled in a graphite cylinder. Plasma temperature was measured using Hb line and C2 Swan band in the upper part of the nozzle and at the entrance of the cylinder respectively. The results show that inside this volume, the plasma temperature is larger than or equal to 4500K and is very sensitive to the arc current.
3D MODELLING OF CARBON BLACK FORMATION AND PARTICLE RADIATION DURING METHANE CRACKING BY THERMAL PLASMA
6
10.1615/HighTempMatProc.v7.i1.80
J. Gonzales
Aguilar
Center for Energy and Processes, Ecole des Mines de Paris, Rue Claude Daunesse B.P.. 207, F-06904 Sophia-Antipolis Cedex, France ; Dpto. De Fisica Aplicada, Universidad de Cantabria, Av. Los Castros s/n, 39005 Santander, SPAIN
I.
Deme
Ecole des Mines de Paris, B.P. 207, F-06904 Sophia Antipolis Cedex, France
L.
Fulcheri
Centre D'Energetique, Ecole Des Mines De Paris; Rue Claude Daunesse, B. P. 207, F-06904 Sophia Antipolis Cedex
T. M.
Gruenberger
Ecole des Mines de Paris, B.P. 207, P-06904 Sophia Antipolis, France
Frederic
Fabry
C. N. R. S., Institut de Science et de Genie des Materiaux et Procedes B. P. 5, Odeillo, F-66125 Font-Romeu Cedex
Gilles
Flamant
CNRS PROMES UPR 8521, Tecnosud, Rambla de la Thermodynamique, 66100 Perpignan, France
Benjamin
Ravary
Centre D'Energetique, Ecole Des Mines De Paris; Rue Claude Daunesse, B. P. 207, F-06904 Sophia Antipolis Cedex
In this work, a steady three dimensional CFD simulation that describes the strong coupling between the complex phenomena existing in the plasma reactor is presented using the commercial software FLUENT ®. The model includes the turbulence effects (by k-e standard model), an electric arc sub-model to describe the time-average Lorentz forces and ohmic heating generated by the three-phase power-supply, the methane transport in an argon plasma, the soot formation from methane decomposition and the radiation calculation. The radiation model takes into account the modification of the absorption coefficient due to the presence of solid carbon particles.
The main computed fields (velocities, temperature and absorption coefficient) are presented and discussed. The influence of operating conditions as argon and methane flow rates and arc current is shown.
HEAVY METALS VOLATILITY STUDY DURING THERMAL PLASMA VITRIFICATION BY OPTICAL EMISSION SPECTROSCOPY
8
10.1615/HighTempMatProc.v7.i1.90
Nuno
Cerqueira
LASEP: Laboratoire d'Analyse Spectroscopique et d'Energétique des Plasmas, UPRES-EA 3269 Faculté des Sciences, Site de Bourges, Université d'Orléans, rue Gaston Berger, BP 4043, 18028 Bourges Cedex France
C.
Vandensteendam
Laboratory of Plasma Chemistry, University of Limoges,123 av. Albert Thomas, 87060 Limoges, France
Jean Marie
Baronnet
Laboratory of Plasma Chemistry, University of Limoges,123 av. Albert Thomas, 87060 Limoges, France
Fly ash issued of incineration of wastes content high proportion of heavy metals salts specially chlorides and sulfates.
According to the volatility of these compounds observed during vitrification of fly ash, a predictive model has been used to simulate the elimination of Pb, Zn and S from the melt as a function of time and temperature for a system including chlorides, oxides and sulfates.
The objective of this work was the experimental study of heavy metals volatility using optical emission spectroscopy. A twin torch plasma system, mounted above a cold crucible with Ar (or Ar + O2) as plasma gas, has been used. The crucible was filled with synthetic glass in which known amounts of metallic salts were added to obtain the same chemical composition as used in the model.
From spectral lines intensities of Ar, the plasma temperature profiles along the observation direction has been first established, before using ratios of spectral lines of Ar and metallic (Pb, Zn) or Cl vapors to reach the evolution of the elements concentrations above the melt. The influence of the atmosphere( Ar or Ar + O2) above the crucible has been studied and differences in elements behaviors have been pointed out.
The results of the spectroscopic measurements have been compared to the ones issued of modeling, in order to validate our model of vaporization.
3D MODEL OF THE ESTABLISHMENT OF A PLASMA ARC BETWEEN TWO AERIAL METALLIC ELECTRODES
6
10.1615/HighTempMatProc.v7.i1.100
B.
Barthelemy
CEA/VALRHO/DEN/DIEC/SCDV/LPIC, BP17171. 30270 Bagnols sur Ceze cedex , France
C.
Girold
CEA/VALRHO/DEN/DIEC/SCDV/LPIC, BP17171. 30270 Bagnols sur Ceze cedex, France
Clarisse
Delalondre
Laboratoire National d'Hydraulique - EDF, 6 Quai Watier - 78400 Chatou - France
Bernard
Paya
Electricite de France - R&D Division - Centre des Renardieres Route de Sens - F-77818 Moret Sur Loing Cedex - France
Jean Marie
Baronnet
Laboratory of Plasma Chemistry, University of Limoges,123 av. Albert Thomas, 87060 Limoges, France
This paper describes the initial results of a 3D flow simulation of a molten glass bath and a transferred electric plasma arc between two aerial metallic electrodes. The calculations were performed as part of a joint CEA-EDF study. The ESTET 3.4 CFD calculation code used to simulate electric arc furnaces in the metallurgical industry was applied here to model glass melting by an oxygen transferred arc plasma in order to optimise the treatment of radioactive waste. This method could be applied to industrial or municipal waste. The high temperature obtained by the plasma allows us to bum the organic fraction of the waste and then, the mineral part of this waste is trapped in me glass melt.
INVESTIGATION ON BISTABILITY IN INDUCTIVELY-COUPLED PLASMA TORCHES WITH NON-CONVENTIONAL COIL
6
10.1615/HighTempMatProc.v7.i1.110
Davide
Bernardi
Universita degli Studi di Bologna, Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (D.I.E.M.) and C.I.R.A.M., Via Saragozza 8, 40123 Bologna, Italy
Vittorio
Colombo
Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (D.I.E.M.) and C.I.R.A.M., Università degli Studi di Bologna, Via Saragozza 8, 40123 Bologna, Italy
Gianni G.M.
Coppa
Istituto Nazionale per la Fisica della Materia and Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
Emanuele
Ghedini
Università degli Studi di Bologna, Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (D.I.E.M.) and C.I.R.A.M., Via Saragozza 8, 40123 Bologna
Andrea
Mentrelli
Universita degli Studi di Bologna, Dipartimento di Ingegneria delle Costruzioni Meccaniche, Nucleari, Aeronautiche e di Metallurgia (D.I.E.M.) and C.I.R.A.M., Via Saragozza 8, 40123 Bologna, Italy
In previous works on ICPTs with split coil [1.2], the Authors pointed out that for a particular choice of the geometric parameters two equilibrium states for the plasma exist for the same induction coil current. In the present study, a deep investigation of the transition between the two states is performed with a time-dependent simulation code, evidencing a sort of hysteresis phenomenon. A parametric study is carried out in order to find threshold parameters for the bistability in different geometries. For some cases, time oscillating behaviour of plasma is found.
OPTICAL SPECTROSCOPIC DIAGNOSTIC OF AN ARGON-HYDROGEN RF INDUCTIVE THERMAL PLASMA TORCH
6
10.1615/HighTempMatProc.v7.i1.120
M.
Benmansour
Laboratoire de Génie des Procédés Plasmas et Traitement de Surface − Université Pierre et Marie Curie − Paris 6 - ENSCP, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05
M.
Nickravech
Laboratoire de Génie des Procédés Plasmas et Traitement de Surface − Université Pierre et Marie Curie − Paris 6 - ENSCP, 11, rue Pierre et Marie Curie, 75231 Paris Cedex 05, France
S.
Darwiche
Laboratoire de Genie des Procedes Plasmas et Traitement de Surface - Université Pierre et Mane Curie- ENSCP 11-13, rue Pierre et Marie Curie 75231 Paris Cedex 05 France
Daniel
Morvan
Laboratoire de Genie des Precedes Plasmas Universite P. et M. Curie, ENSCP 11 rue P. et M. Curie 75005 Paris France
Jacques
Amouroux
Laboratoire de Genie des Precedes Plasmas Universite P. et M. Curie, ENSCP 11 rue P. et M. Curie 75005 Paris France
The hydrogenation of silicon material proves great advantages concerning its photovoltaic properties and secure a key for the elimination of crystalline defects during the basaltic growth of the crystal. In our process, silicon particles are hydrogenated in the thermal plasma torch at atmospheric pressure. So, the aim of this work is to characterise the physical properties of the plasma flow in order to understand the interaction appearing between particles and hydrogenated plasma flow during the treatment. Highly excited states of atomic hydrogen, responsible of the silicon hydrogenation, have been detected in the plasma. These atomic hydrogen lines have been used to determine the electronic density on the plasma axis. Electronic temperature of different plasma mixture have been obtained by the Boltzmann plot method.
ENTRAINMENT OF AMBIENT AIR INTO AN ARGON ICP
9
10.1615/HighTempMatProc.v7.i1.130
Marco J.
van de Sande
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
P.
van Eck
Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
Antonio
Sola
Departamento de Fisica Aplicada, Universidad de Cordoba, 14071 Cordoba, Spain
Antonio
Gamero
Departamento de Fisica Aplicada, Universidad de Cordoba, 14071 Cordoba, Spain
Joost J. A. M.
van der Mullen
Department of Applied Physics, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
Entrainment of air molecules into spectrochemical ICPs, which are normally operated in the open air, may influence the plasma's behaviour, especially so at its edge. In this study, the air concentration and temperature just outside the plasma were measured by rotational Raman scattering. The electron density and temperature inside the plasma were determined by Thomson scattering. By using both techniques simultaneously and with spatial resolution, positioning errors are kept to a minimum. Just within the torch, but outside the plasma region, the gas temperature is well below 1000 К. and the air concentration is less than 10%. No region where both electrons and air were present in detectable amounts (1019 and 1024 m-3 respectively) was observed. This suggests that air entrainment does not play a significant role in the plasma dynamics of the ICP, perhaps with an exception at the outermost boundary.
CALCULATION OF SILICON PARTICLES DYNAMICS, HEAT AND MASS TRANSFERS IN THERMAL PLASMAS. EFFECT OF PARTICLES VAPORIZATION
14
10.1615/HighTempMatProc.v7.i1.140
Jacques
Amouroux
Laboratoire de Genie des Precedes Plasmas Universite P. et M. Curie, ENSCP 11 rue P. et M. Curie 75005 Paris France
Sergey V.
Dresvin
Laboratory of Electrotechnological and Plasma Installation of Polytechnic Institute -SPb State Polytechnical University, 29 Polytechnicheskaya Str., 195251 Saint-Petersburg, Russia
Daniel
Morvan
Laboratoire de Genie des Precedes Plasmas Universite P. et M. Curie, ENSCP 11 rue P. et M. Curie 75005 Paris France
L.
Ouvrelle
LGPPTS, ENSCP, 11 rue P. & M. Curie, 75005 Paris, France
D.
Ivanov
St. Petersburg State Polytechnic University, 29 Politekhnicheskaya Str., St. Petersburg, 195251, Russia
S. G.
Zverev
St. Petersburg State Polytechnic University, 29 Politekhnicheskaya Str., St. Petersburg, 195251, Russia
O.
Feigenson
SPb State Polytechnic University, Polytechnic Str 29, 195251 Saint Petersburg, Russia
A.
Balashov
SPb State Polytechnic University, Polytechnic Str 29, 195251 Saint Petersburg, Russia
In this paper there were calculated the motion and the heating of a silicon particle in the RF ICP torch which is used in the Laboratoire de Genie des Procedes Plasmas et Traitement de Surfaces (Universite P. et M. Curie, France) for powder treatment and which works at the frequency of 5 MHz, the plasma power being 10 kW.
The model for the particle heating takes into account the following processes: the particle heating, its melting, vaporization (including losses of energy by vaporization and heating of the vapor cloud) and evaporation (boiling). The temperature inside the particle is supposed uniform.
A new way of correction of the vaporization calculation is proposed. In order to evaluate the effect of the particle vaporization on the particle heating, several variants were calculated: without vaporization and with vaporization calculated by different equations.
The way of vaporization calculation was chosen on the basis of comparison between calculations and experimental data.
TWO-TEMPERATURE COMBINED DIFFUSION COEFFICIENTS IN ARGON-HELIUM THERMAL PLASMAS
8
10.1615/HighTempMatProc.v7.i1.150
Jacque
Aubreton
SPCTS University of Limoges, 123 av. A. Thomas, 87060 Limoges cedex, France
M. F.
Elchinger
SPCTS University of Limoges, 123 av. A. Thomas, 87060 Limoges cedex, France
V.
Rat
PCTS -CNRS UMR 6638, University of Limoges, 123 av. A. Thomas, 87060 Limoges cedex, France
Pierre
Fauchais
Laboratoire Sciences des Procedes Ceramiques et de Traitements de Surface UMR CNRS 6638 University of Limoges 123 avenue Albert Thomas, 87060 LIMOGES - France
Anthony B.
Murphy
CSIRO Manufacturing Flagship, Sydney, Australia
From the derivation of two-temperature diffusion number fluxes of species proposed by Rat et al and that of ambipolar diffusion coefficients, combined diffusion coefficients introduced by Murphy at equilibrium are extended to non-equilibrium thermal plasmas, where the kinetic temperature of electrons Te is different from that of heavy species Th.
Two-temperature ordinary and thermal combined diffusion coefficients are calculated in an argon-helium plasma at atmospheric pressure up to 30,000 К. Plasma composition is obtained using a non-equilibrium constant method. The dependence on the electron temperature of combined diffusion coefficients is analyzed for different mole percentages of argon in the mixture and for different values of the non-equilibrium parameter q = Te/Th
Similar behaviors to those obtained at equilibrium are highlighted with a decrease in the combined diffusion coefficients, at fixed electron temperature, as q increases.
MODELING OF THE RADIATIVE EMISSION OF A PLASMA SURROUNDING A SPACE PROBE ENTERING MARS ATMOSPHERE
11
10.1615/HighTempMatProc.v7.i1.160
M. Line
da Silva
Laboratoire d'Aerothermique, CNRS, 1C av. de la Recherche Scientifique, 45071 Orleans cedex 2, France
V.
Lago
Laboratoire d'Aerothermique du CNRS 1C Avenue de la Recherche Scientifique, 45071 Orleans Cedex 2, France
E.
Bedjanian
Laboratoire d'Aerothermique, CNRS, 1C av. de la Recherche Scientifique, 45071 Orleans cedex 2, France
A.
Lebehot
Laboratoire d'Aerothermique du CNRS 1C Avenue de la Recherche Scientifique, 45071 Orleans Cedex 2, France
S.
Mazouffre
Laboratoire d'Aerothermique, CNRS, 1C av. de la Recherche Scientifique, 45071 Orleans cedex 2, France
Z.
Szymanski
Instytut Podstawowych Problemow Techniki, PAN Swietokrzyska 21, 00-049 Warszawa, Poland
Michel A.
Dudeck
ICARE Inst.-CNRS and University of Paris 6, 75252 Paris, France
Z.
Peradzynski
Instytut Podstawowych Problemow Techniki - PAN, Swietokrzyska 21,00-149 Warszawa, Polska
A.
Chikhaoui
IUSTI, Universite de Provence, 5 rue Enrico Fermi, 13453 Marseille cedex 13, France
P.
Boubert
IUSTI, Universite de Provence, 5 rue Enrico Fermi, 13453 Marseille cedex 13, France
Spectral emission of the plasma formed in front of a space vehicle entering the upper layer of Mars atmosphere is analysed. The high temperatures behind a hypersonic shock wave leads to dissociation and ionisation of the molecules found in the Martian atmosphere. The chemical reactions responsible for the formation of a Martian plasma are presented. A simulation of the spectra of some of the most important emitting systems is performed (numerical code SESAM), and a comparison with experimental spectra obtained in a low pressure arc-jet wind tunnel is presented. The influence on the shape of the simulated CN violet spectra, of the apparatus function, vibration and rotation temperatures is studied.