Literatura académica sobre el tema "Plasmas froids – Modèles mathématiques"
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Tesis sobre el tema "Plasmas froids – Modèles mathématiques"
Layeillon, Lise. "Analyse et modélisation du fonctionnement d'un réacteur de dépôt de silicum amorphe hydrogéné assisté par plasma". Toulouse, INPT, 1992. http://www.theses.fr/1992INPT042G.
Texto completoGuiberteau, Emmanuel. "Modélisation d'une décharge DC pulsée dans l'azote : simulations numériques à l'aide d'un code couplant la dynamique des particules chargées à celle du gaz neutre : comparaisons avec l'expérience". Nancy 1, 1998. http://docnum.univ-lorraine.fr/public/SCD_T_1998_0291_GUIBERTEAU.pdf.
Texto completoThis work deals the modeling of a dc pulsed diode type discharge used for iron and steel nitriding. The present research aimed at a better understanding of the processes occuring in such plasmas in order to attain an optimization of the surface treatment process. In a first stage we adapted an existing electrical modeling to the experimental results obtained from electrostatic probe and emission spectroscopy measurements. These preliminary results showed a roughly good agreement between the modeling and the experiment and pointed out the limits of this simulation. Two improvements have thus been made to this basic model: a better description of the electron population using a monoenergetic electron beam ; a coupling with a modeling of the neutral gas dynamics. The first improvement led to a better description of the various regions of the discharge (in particular the negative glow) and to get an excellent agreement between numerical and experimental results in the case of short duration impulse discharges. The second improvement showed the importance and the need for taking into account the heating of neutral gas in the case of discharge on-time greater than a few hundreds of microseconds
Dubus, Nicolas. "Contribution à l'étude thermique d'un réacteur à décharge à barrière diélectrique". Poitiers, 2009. http://theses.univ-poitiers.fr/theses/2009/Dubus-Nicolas/2009-Dubus-Nicolas-These.pdf.
Texto completoThis thesis aims to study the thermal behaviour of a laboratory Dielectric Barrier Discharge (DBD) reactor. An experimental study was first realized to measure temperatures at different points of the reactor by using optic fibres. These measurements were performed in transient and steady states. To examine the influence of heat losses , not insulated and insulated reactors were considered. The influence of the nature and the form of the applied voltage was else considered. Experiments were conducted with a sinusoidal voltage and a pulsed power supply
Gaychet, Sylvain. "Modélisation des décharges couronnes négatives : Application à la précipitation électrostatique". Pau, 2010. http://www.theses.fr/2010PAUU3038.
Texto completoElectrostatic precipitation presents many advantages from the nuclear wastes treatment's point of view. Indeed, this kind of process can capture submicronic particles without producing secondary wastes (no filter media) and without pressure looses in the exhaust circuit. The work presented in this thesis concerns the study of negative corona discharges in air at atmospheric pressure occurring in an electrostatic precipitator (ESP) developed by the CEA (Atomic Energy Committee). The aim of this study is to determine how the electrostatic precipitation dedicated phenomena, especially the specific high voltage generator, the gas temperature and the fact that particles are flowing through the gap then collapsing on the electrodes, modify the discharge to improve the efficiency of ESPs. This work is based on a fundamental experimental study of the negative corona discharge and on numerical simulations of this discharge under conditions close to those of the lab scale ESP developed by the CEA
Zaafrani, Ibtissem. "Dynamique et stabilisation d’un plasma magnétique froid". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0312.
Texto completoIn this thesis, we consider a linearized Euler-Maxwell model for the propagation and absorption of electromagnetic waves in a magnetized plasma. Two types of boundary conditions are considered: perfectly conducting on the whole boundary and Silver-Müller, homogeneous or not, on part of it. First, I establish the equations of the model and show its well-posedness by the theory of semigroups. Then, I am interested in the stabilization of the model. First, I carry out a study on the long- term asymptotic behavior of the solution. I show that it decreases towards zero under certain physically reasonable assumptions. I conclude that it converges to a non-zero stationary state in a larger energy space. This stationary state is linked to the topology properties of the domain, and is expressed as a function of the initial data. Secondly, I study the energy decay rate by using the frequency domain method. I establish a polynomial decay for both boundary conditions. I also prove a conditional exponential decay result in the homogeneous Silver-Müller case. In the perfectly conducting case, we show that the Euler-Maxwell system is not exponentially stable. We conclude by a result of convergence towards the time-harmonic regime in the presence of a harmonic forcing. Among the main difficulties encountered, the resolvent of the evolution operator is not compact and the internal absorption acts only on the fluid variables. No homogeneity assumption is made, and the topological and geometrical assumptions on the domain are minimal. These results appear strongly linked to the spectral properties of various matrices describing the anisotropy and other plasma properties. Finally, we extend those results to the case of a vacuum-plasma interface problem
Quinio, Géraldine. "Modélisation numérique de la génération d’un plasma d’air dans un écoulement aérodynamique". Toulouse, INSA, 2005. http://eprint.insa-toulouse.fr/archive/00000445/.
Texto completoOrder to reduce the flash points in air intake of aircraft, a considered deviee consists in the partial ionisation of the air around the air intake. The aim of the thesis is to develop mathematical and numerical models in order to apprehend the main physical mechanisms which occur in the generation of air plasmas at atmospheric pressure in air flows. An asymptotic analysis of simple ionization kinetics of air flows at atmospheric pressure is first proposed. The existence of the plasma depends on the value of the flow velocity relative to a threshold value and on the existence of metastables which detach electrons from negative ions. Secondly, we were interested in the modelling of capillary discharges which allows the genera tion of a homogeneo us discharge in air at atmospheric pressure. A OD model has been made in order to understand the main physical mechanisms occurring in the discharge initiation. The numerical simulations shows the wall phenomena take an important place in the operation of the discharge. Lastly, a 2D model is developed to model a negative tip/plane corona discharge in air flows. The mode! consists of a system of non-linear convection/diffusion /reaction equations coupled with the Poisson equation. The current induced by the plasma circulation in the extemal circuit is Iinked with the potential through an ordinary differential equation in time. The numerical simulations show that when the flow velocity becomes important, a periodical formation of plasma channels carrying away by the air flow is observed
Irimiciuc, Stefan-Andrei. "Experimental and theoretical studies on the dynamics of transient plasma plumes generated by laser ablation in various temporal regimes". Thesis, Lille 1, 2017. http://www.theses.fr/2017LIL10193/document.
Texto completoLaser ablation methods exhibit a fast development in various application fields, as materials processing, medicine, nuclear fusion or analytical sciences. Despite important advances in the knowledge of the complex laser-matter interactions involved in this process, there is still need for better fundamental understanding and modeling. The aim of this work was to experimentally and theoretically investigate the dynamics of transient plasmas generated by laser ablation in various regimes (ns, ps, fs), and to try to correlate the observed behavior with the physical properties of the ablated materials We implemented space- and time-resolved optical, spectroscopic and electrical methods for the study of single-component metallic targets and of complex chalcogenide targets. This led to a space-time mapping of the main plasma parameters. The study performed in actual Pulsed Laser Deposition (PLD) conditions revealed some peculiar effects like ionic oscillations or plume reflection at the substrate. A compact fractal hydrodynamic model was developed to simulate the laser-produced plasma dynamics. The theoretical model accurately describes the spatial and temporal evolution of the main plasma parameters (electronic temperature, expansion velocities, particle number density, Debye length, plasma potential). We report for the first time empirical relations connecting these plasma parameters with the physical properties (electrical/thermal conductivity, atomic mass, heat of vaporization) of the target. These relationships transcend all three ablation regimes (ns, ps, fs)
Annušová, Adriana. "Étude de la cinétique des décharges et post-décharges excitées à hautes et très hautes fréquences dans les mélanges azotés". Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10089/document.
Texto completoThis work focuses on the study of the kinetics of discharges and post-discharges in flowing nitrogen and nitrogen mixtures at moderate pressures. The kinetic modeling was performed on the basis of experimental results in order to understand the production and destruction processes of the species presents in the plasma. The thesis is divided into two parts according to the type of the discharge and gas mixtures studied. In the frame of the part A, a N2-Ar discharge generated by an original helical cavity excited at 27 MHz is examined by optical emission spectroscopy. Based on experimental results, a global kinetic model coupled with a model of the vibrational distribution function of the N2(C3Pu, v’=0-4) state have been developed. These models enable the analysis of our results and demonstrate the importance of the mechanisms involving metastable nitrogen and argon species, i.e. N2(A3Su+) et Ar(3P0,2). In Part B, discharges in mixtures of N2-O2 generated by a 433 MHz coaxial cavity were studied along with the afterglows by optical emission spectroscopy and mass spectrometry methods. A 0D kinetic model, based on experimental results, is associated with a flow simulation in order to qualitatively reproduce the evolution of concentrations and predict the nature of the environment created by the discharge as well as its characteristics for the applications of thin layer deposits of organosilicon materials for microtechnology
Abd, Jelil Radhia. "Modélisation de la relation entre les paramètres du procédé plasma et les caractéristiques de la qualité du matériau textile par apprentissage de données physiques". Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10017/document.
Texto completoAtmospheric plasma treatment seems to be a good way to treat quickly, cheaply and ecologically textile material surfaces. Despite these advantages, it is extremely difficult to understand the complex non-linear relationship between the plasma processing parameters and the final properties of materials. Therefore, the study and optimization of such process must be based on an exploitation of intelligent techniques such as fuzzy logic and neural networks. In a first part, the impact of atmospheric air Dielectric Barrier Discharge (DBD) plasma treatment is studied on different types of polyester and viscose woven fabrics. In order to get a better understanding on how the structure of woven fabrics influence on the results of the plasma treatment, a selection of the most relevant parameters was carried out by using a fuzzy logic based sensitivity variation criterion. This work shows that that the electric power, the treatment speed, the composition, the fibers fineness, the air permeability, the weave construction and the summit density have an influence on the wettability and the capillarity of fabrics. Lastly, a neural network approach was developed to predict the relationship between the selected input parameters and the fabric hydrophilic properties. Very satisfactory results were obtained and show a good capacity of generalization. Moreover, a quantitative analysis based on the weights of connections was conducted to analyze the relative importance of the input parameters. The results of this analysis are coherent with those obtained by using the fuzzy logic based sensitivity variation criterion. Thus, this finding confirms, on the one hand, the influence of the selected parameters and, on the other hand, it shows the efficiency of neural networks
Daadaa, Rihab. "Formulation mixte augmentée d’un modèle « Full-wave » tridimensionnel dans un plasma froid : analyse numérique d’une approximation ℙ₂-ℙ₁". Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0307.
Texto completoThe object of this thesis is to study a numerical simulation method of a so-called “Full-wave” model of the propagation in a tokamak of an electromagnetic wave injected by a set of antennas installed in the boundary of the containment chamber. A Lagrange finite element approximation method is deployed. In the first chapter, we introduced the physical model considered to describe the propagation of an electrostatic wave of a frequency close to hybrid resonance in a so-called cold plasma, plasma confined by a magnetic field inside a tokamak. The propagation of electromagnetic waves is modeled by Maxwell's equations. This work contemplates an approximation of the time-harmonic solution. In the second chapter, we recall the mixed and mixed variational formulations already studied in the past. These formulations allow us to find solutions in (H¹(Ω))³ and therefore a conformal finite element approximation in this space. Chapter three is dedicated to the presentation of the discretization of the model's equations in three dimensions of space. In chapter four it is demonstrated the well-posed character of the discrete system of equations when one considers a Taylor-Hood type approximation ℙ₂-ℙ₁. In this section, we proved a result about the existence and the uniqueness of the solution in the case of a polyhedral “torus”. Chapter 5 is dedicated to numerical simulations. First are introduced the terms of the dielectric tensor K and its derivatives, needed to mount the stiffness matrix of the system. The first simulations concern the case where the density of electrons and ions is constant. Then results are presented in the case where densities have a parabolic profile. It is also considered the case where the wave vector is a function of the distance at the center of the tokamak
Libros sobre el tema "Plasmas froids – Modèles mathématiques"
Centre de recherches en physique de l'environnement terrestre et planétaire (Issy-les Moulineaux, Hauts-de-Seine), ed. Tutorial courses. Toulouse: Cepadues-Ed., 1989.
Buscar texto completoN, Dnestrovskiĭ I͡U. Numerical simulation of plasmas. Berlin: Springer-Verlag, 1986.
Buscar texto completo1925-, Killeen J., ed. Computational methods for kinetic models of magnetically confined plasmas. New York: Springer-Verlag, 1986.
Buscar texto completo1952-, Itoh S. I. y Itoh K, eds. Plasma and fluid turbulence: Theory and modelling. Bristol: Institute of Physics Pub., 2003.
Buscar texto completoItoh, K., 吉澤 徴 y S. I. Itoh. Plasma and Fluid Turbulence. Taylor & Francis Group, 2010.
Buscar texto completoItoh, K., 吉澤 徴 y S. I. Itoh. Plasma and Fluid Turbulence: Theory and Modelling. Taylor & Francis Group, 2002.
Buscar texto completoItoh, K., 吉澤 徴 y S. I. Itoh. Plasma and Fluid Turbulence: Theory and Modelling. Taylor & Francis Group, 2002.
Buscar texto completoItoh, K., 吉澤 徴 y S. I. Itoh. Plasma and Fluid Turbulence: Theory and Modelling. Taylor & Francis Group, 2002.
Buscar texto completoItoh, K., 吉澤 徴 y S. I. Itoh. Plasma and Fluid Turbulence: Theory and Modelling. Taylor & Francis Group, 2002.
Buscar texto completoItoh, K., 吉澤 徴 y S. I. Itoh. Plasma and Fluid Turbulence: Theory and Modelling (Series in Plasma Physics). Taylor & Francis, 2002.
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