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Dive into the research topics where Michel Touzeau is active.

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Featured researches published by Michel Touzeau.


IEEE Transactions on Plasma Science | 1995

Kinetic model of a low-pressure N/sub 2/-O/sub 2/ flowing glow discharge

Boris F. Gordiets; Carlos M. Ferreira; Vasco Guerra; J Loureiro; Jacimar Nahorny; D Pagnon; Michel Touzeau; M Vialle

A self-consistent kinetic model is developed to study dc flowing glow discharges in N/sub 2//O/sub 2/ mixtures. This model includes the calculation of electron energy distribution functions and electron rate coefficients coupled with detailed vibrational kinetics of N/sub 2/ molecules, chemical kinetics taking into account a large set of neutral, excited and charged species, interaction of N and O atoms at the discharge tube wall, and the thermal balance of the discharge. The results of this model agree reasonably well with the measurements of the electronic density, the gas temperature, the reduced electric field, the vibrational temperature of N/sub 2/ and the concentration of O, N atoms, NO molecules, N/sub 2/(C), N/sub 2//sup +/(B), and NO(/spl gamma/) excited states. The comparison was performed in a N/sub 2/-O/sub 2/ discharge at pressure p=2 Torr, for discharge currents I=15, 30, and 80 mA, a flow rate Q=100 sccm, and O/sub 2/ percentages ranging from 0 up to 100%,. >


Journal of Physics D | 1995

On the use of actinometry to measure the dissociation in O2 DC glow discharges: determination of the wall recombination probability

D Pagnon; J Amorim; J Nahorny; Michel Touzeau; M Vialle

A study has been performed to re-investigate the actinometric technique used to determine the absolute concentration of O atoms in DC O2 flowing glow discharges for pressures ranging from 0.36 to 2 Torr and discharge currents ranging from 5 to 80 mA in Pyrex tubes of three different diameters (16, 7 and 4 mm). Actinometric measurements using O(3P-3S) 844 nm, O(5P-5S) 777 nm and Ar(2p1-1S2) 750 nm transitions are compared to VUV absorption spectrometry. The choice of the excitation cross sections for the calculations of atomic excitation rates as a function of the reduced electric field using a Boltzmann code and the contribution of the quenching processes of the excited states are discussed. The dissociation ratio (O)/(O2) can be determined from the ratio of intensities I844/I750 by the relation (O)/(O2)=C3P2p1 I844/I750. We have found that C3P2p1 remains constant (C3P2p1=2.6*10-3) throughout the range of experimental conditions investigated. The recombination probability gamma of the O atoms at the wall is calculated and correlated to the wall temperature of the Pyrex tubes. The variation of the recombination probability as a function of the wall temperature is fitted by the relation gamma =0.94exp(-1780/Twall) for 300


Journal of Physics D | 1991

ELECTRON AND HEAVY-PARTICLE KINETICS IN THE LOW PRESSURE OXYGEN POSITIVE COLUMN

G. Gousset; C. M. Ferreira; Mario J. Pinheiro; P A Sá; Michel Touzeau; M Vialle; J Loureiro

A kinetic model for the low-pressure oxygen positive column is presented and discussed. The model is based on the electron Boltzmann equation and the rate balance equations for the dominant heavy-particle species, which are solved simultaneously in order to take into account the coupling between the electron and the heavy-particle kinetics. The effects of vibrationally excited molecules, dissociated atoms and metastable states on the electron kinetics are analysed in detail. The predicted populations of O2(X3 Sigma ), O2(a1 Delta ), O(3P), and O- are shown to agree satisfactorily with previously reported measurements. A combination of this kinetic model with the continuity and transport equations for the charged species e, O-, and O2+ is shown to provide characteristics for the maintenance field that agree reasonably well with experiment.


Plasma Chemistry and Plasma Processing | 1987

Experimental study of a d.c. oxygen glow discharge by V.U.V. absorption spectroscopy

G. Gousset; Pierre Panafieu; Michel Touzeau; M Vialle

Vacuum ultraviolet absorption spectroscopy has been used to measure the concentration of oxygen molecules O2(3∑), metastable singlet O2(1Δ) molecules, atoms, and ozone in a d.c. glow discharge. The axial electric field, the electronic density, and the gas temperature are also determined. This set of measurements is presented for the positive column of a glow discharge created in a 1.6-cm-diameter Pyrex tube, for a pressure between 0.2 and 5 Torr and a d.c. current up to 80 mA.


Journal of Physics D | 1988

Quasi-neutral theory of positive columns in electronegative gases

C. M. Ferreira; G. Gousset; Michel Touzeau

A theory of the positive column in electronegative gases based on fluid-type momentum equations to describe charged particle motion is presented. It is assumed that quasi-neutrality conditions prevail and the ion inertial terms are neglected. The positive ions are assumed to be created by electron collisions with neutral molecules and the negative ions to be formed by dissociative electron attachment and destroyed by detachment in reactions with neutral species. The mathematical formulation consists of a two-point boundary value problem involving two independent parameters, functions of collisional and transport data, and two eigenvalues. One of these is the central ratio of the negative ion density to the electron density, while the other is related to the ionisation-loss balance and embodies a discharge characteristic for the maintenance field. These eigenvalues and the radial density distributions of the charged species were calculated for a wide range of variation of the independent parameters. An application of the theory to a positive column in oxygen is given as an illustrative example.


Journal of Physics B | 1981

Population of N2(A 3Σu+) metastable states in a pure nitrogen glow discharge

G Cernogora; L Hochard; Michel Touzeau; C Matos Ferreira

The concentration of the nitrogen metastable molecule N2(A 3 Sigma u+) is determined in a pure nitrogen glow discharge as a function of the pressure (from 0.1 to 2 Torr) and of the discharge current (up to 30 mA cm-2) using the optical absorption of the first positive system bands. The absorption maximum is of the order of 2% corresponding to a N2(A 3 Sigma u+, nu =0) concentration of about 1.4*1012 cm-3. Measurements of the concentration of nitrogen atoms, the electronic field are also reported. A kinetic model indicates that the N2(A) molecules are created by electronic excitation from ground-state molecules and lost mainly by diffusion to the walls and collisions with N(4S) atoms.


Applied Physics Letters | 2004

Room temperature synthesis of carbon nanofibers containing nitrogen by plasma-enhanced chemical vapor deposition

Tiberiu Minea; S. Point; A. Granier; Michel Touzeau

This letter reports low-pressure, room-temperature growth of carbon nanofibers containing nitrogen by plasma chemical vapor deposition arrangement. By alternating pure acetylene plasma and afterglow pure nitrogen high dense plasma, a fine control of the fibers growth kinetic is obtained. This layer-by-layer deposition technique takes advantage of nitrogen chemical etching effects during the growth of nitrogen-doped carbon nanofibers.


Journal of Physics D | 1995

Experimental and theoretical investigation of a N2-O2 DC flowing glow discharge

J Nahomy; C. M. Ferreira; B Gordiets; D Pagnon; Michel Touzeau; M Vialle

A study has been performed to investigate the kinetics of production of N atoms and NO molecules in DC N2-O2 flowing glow discharges at pressure rho =2.0 Torr for discharge currents I=15, 30, 80 mA. Measurements of the plasma parameters, reduced electric field E/N, electronic density ne, as well as of the gas temperature Tg, the vibrational temperature Tnu of N2 molecules and the concentration of N atoms and NO molecules have been carried out over the whole range of oxygen percentages (0-100%). This set of measurements is compared to the results of a one-dimensional model including a detailed vibrational kinetics, a large number of chemical reactions and the thermal balance of the discharge.


Plasma Sources Science and Technology | 2001

Transient phenomena in closed electron drift plasma thrusters : insights obtained in a french cooperative program

André Bouchoule; Ch Philippe-Kadlec; M Prioul; F Darnon; M Lyszyk; L Magne; D Pagnon; S Roche; Michel Touzeau; S. Béchu; P. Lasgorceix; N. Sadeghi; N Dorval; J-P Marque; J Bonnet

This paper presents some aspects of the research developed in the frame of a coordinated program launched in France in 1996 and devoted to plasma thrusters for space technologies. Relevant results of physical studies have been selected from the literature with the addition of recent original results. The thrusters within the scope of this research are diagnostic equipped versions of industrial realizations, in a thrust level range of 0.1 N and electrical power 1.5 kW. The optical and electrical diagnostics concern studies of the thruster plasma and of the thruster plume. Transient phenomena in these two regions, related to discharge current fluctuations or oscillations on a typical time scale of 40 µs, have been space-time characterized. This has been achieved by developing a large panel of diagnostics including RFEA, Langmuir probes, OES, fast camera imaging and electron drift Hall current probe. They lead to a coherent representation of these phenomena , in rather good qualitative agreement with 1D modelling. But they emphasize also the importance of 2D effects. Insights obtained through combined LIF (on Xe+ ions) and OES diagnostics are also presented. They concern the ionization-acceleration region in the thruster plasma, where intrusive diagnostics are disturbing in nature, and open a new step for a significant improvement of the detailed understanding of these thrusters. Such improvements are required when looking at the final goal of a predicable modelling simulation able to help the design of optimized structures at various thrust levels, in spite of the important work devoted to these devices in the former USSR and by Russian teams in Moscow at the MIREA, MAI-RIAME and KOURCHATOV Institutes.


Plasma Sources Science and Technology | 2007

Experimental study of a pre-ionized high power pulsed magnetron discharge

Petr Vašina; Marcel Meško; Jean-Christophe Imbert; M. Ganciu; Caroline Boisse-Laporte; L de Poucques; Michel Touzeau; D Pagnon; Jean Bretagne

This paper is focused on experimental studies of a high power pulsed magnetron discharge stabilized by low current pre-ionization. Time resolved studies were performed for a Cu target by optical emission spectroscopy and electrical measurements for different pressures of Ar buffer gas. Due to the elimination of the statistical delay time and a fast discharge current rise the quasi-stationary state was reached in 6 µs. The quasi-stationary state is characterized by an extremely high and pressure independent discharge current density of ~10 A cm−2 and stable Cu+ and Cu++ emissions. Such fast discharge dynamics permits the magnetron cathode current to be driven with a pulse of duration of the order of a few µs, significantly shorter than in other devices. During this short time, the plasma does not have time to undergo the transition from the glow to the arc discharge even at the extremely high cathode loads met in our case. Different stages of the fast discharge development are identified and the composition of the magnetized plasma as a function of the pressure is discussed in detail.

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D Pagnon

University of Paris-Sud

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M. Ganciu

University of Paris-Sud

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L de Poucques

Centre national de la recherche scientifique

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