Book Description
La turbulence tridimensionnelle se caractérise par sa capacité à transférer de l'énergie des grandes vers les petites échelles où elle est finalement dissipée. Lorsqu'elle se produit dans un plasma non-collisionnel comme le vent solaire, une modélisation cinétique semble a priori nécessaire. Toutefois, la complexité d'une telle approche limite les développements théoriques et condamne les expériences numériques à se restreindre à des nombres de Reynolds peu élevés. Dans quelles mesures un modèle mono-fluide comme la MHD Hall permet-il de rendre compte des phénomènes observés dans le vent solaire aux échelles sub-ioniques ? C'est la problématique à laquelle s'est attaquée cette thèse. L'idée directrice de ce travail est de tirer profit de la relative simplicité des modèles fluides et de la puissance algorithmique des méthodes pseudo-spectrales pour aborder la turbulence du vent solaire par des simulations numériques directes tridimensionnelles massivement parallèles à grands nombres de Reynolds. Ces simulations numériques ont permis de mettre en évidence l'existence d'une brisure spontanée de symétrie chirale en turbulence MHD Hall incompressible, ainsi que l'existence d'un nouveau régime appelé ion MHD (IMHD). Un modèle phénoménologique a été proposé pour rendre compte de ces résultats et de nouvelles prédictions ont été faites, puis confirmées numériquement. Enfin, l'étude de l'effet d'un fort champ magnétique uniforme sur la dynamique turbulente a permis de confirmer pour la première fois une ancienne conjecture. L'inertie des électrons a ensuite été prise en compte toujours dans un modèle fluide. Par une approche hydrodynamique classique, une loi universelle a été obtenue pour les fonctions de structure d'ordre trois. L'ensemble de ces résultats est qualitativement en accord avec les mesures in situ du vent solaire et remet en cause le paradigme selon lequel les raidissements successifs du spectre des fluctuations magnétiques sont provoqués nécessairement par des phénomènes d'origine cinétique. De manière plus générale, cette thèse soulève des questions fondamentales sur les processus non-collisionnels de dissipation dans les plasmas turbulents.
Author: CHADI.. SALEM Publisher: ISBN: Category : Languages : fr Pages : 309
Book Description
CE TRAVAIL EST LIE A UN PROBLEME CLE, RELEVANT A LA FOIS DE LA PHYSIQUE SPATIALE ET DE LA PHYSIQUE FONDAMENTALE, QUI EST LA CARACTERISATION DES PHENOMENES DISSIPATIFS DANS UN MILIEU TURBULENT FAIBLEMENT COLLISIONNEL. DE PAR SES PROPRIETES QUE L'ON MESURE IN-SITU GRACE AUX SONDES SPATIALES, LE VENT SOLAIRE CONSTITUE UN LABORATOIRE IDEAL POUR CE TYPE D'ETUDES. LE BUT DE CETTE THESE EST D'ANALYSER LES FLUCTUATIONS ASSOCIEES AU VENT SOLAIRE ET DE DONNER, POUR LA PREMIERE FOIS, UNE VUE GLOBALE DES PHENOMENES AYANT LIEU SUR UNE TRES GRANDE GAMME D'ECHELLES, ALLANT DES ECHELLES MACROSCOPIQUES MHD (BASSES FREQUENCES) AUX ECHELLES CINETIQUES (HAUTES FREQUENCES), OU LA DISSIPATION EST SUPPOSEE JOUER UN ROLE IMPORTANT. NOUS UTILISONS POUR CELA LES OBSERVATIONS FOURNIES PAR LA NOUVELLE GENERATION D'INSTRUMENTS (MESURANT LES ONDES ET LES PARTICULES) EMBARQUES SUR LA SONDE SPATIALE WIND, DONT LES HAUTES RESOLUTIONS TEMPORELLES (JUSQU'A UNE DIZAINE DE MICROSECONDES) ET SPECTRALES (QUELQUES HZ) N'ONT JAMAIS ETE ATTEINTES AUPARAVANT DANS LE VENT SOLAIRE. CETTE HAUTE RESOLUTION A PERMIS DE REVELER QUE, CONTRAIREMENT A LA TURBULENCE A BASSE FREQUENCE, LES ONDES A HAUTE FREQUENCE SONT TRES COHERENTES. CE TRAVAIL SE DIVISE EN TROIS PARTIES : (1) L'ETUDE DES ONDES ELECTROSTATIQUES COHERENTES A PARTIR DE L'ANALYSE DU BRUIT ELECTROMAGNETIQUE A HAUTE FREQUENCE MESURE PAR L'EXPERIENCE WAVES ; (2) L'ETUDE DES PROPRIETES GLOBALES DES PROTONS ET DES ELECTRONS DU VENT SOLAIRE VIA L'ANALYSE DES FONCTIONS DE DISTRIBUTION DES PARTICULES OBTENUES PAR L'EXPERIENCE 3D-PLASMA ; (3) L'ETUDE DE LA TURBULENCE A BASSE FREQUENCE A PARTIR DU CHAMP MAGNETIQUE MESURE PAR L'EXPERIENCE MFI ET DES DONNEES PARTICULES OBTENUES PAR L'EXPERIENCE 3D-PLASMA.
Author: Charles Vincent Publisher: Springer Science & Business Media ISBN: 3662045842 Category : Technology & Engineering Languages : en Pages : 322
Book Description
Jointly published with INRA, Paris. Pesticide resistance is becoming more frequent and widespread with more than 500 insect species known to have become resistant to synthetic insecticides. On the other hand, consumers increasingly demand agricultural products without any pesticide residues. This book, for the first time, shows the alternative: solely physical methods for plant protection by means of thermal, electromagnetic, mechanical and vacuum processes. A glossary rounds up this extremely valuable book.
Author: Ahmed Belasri Publisher: Springer Nature ISBN: 9811554447 Category : Technology & Engineering Languages : en Pages : 659
Book Description
This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.
Author: Thierry Passot Publisher: American Mathematical Soc. ISBN: 0821837230 Category : Science Languages : en Pages : 322
Book Description
This book covers a variety of topics related to kinetic theory in neutral gases and magnetized plasmas, with extensions to other systems such as quantum plasmas and granular flows. A comprehensive presentation is given for the Boltzmann equations and other kinetic equations for a neutral gas, together with the derivations of compressible and incompressible fluid dynamical systems, and their rigorous justification. Several contributions are devoted to collisionless magnetized plasmas. Rigorous results concerning the well-posedness of the Vlasov-Maxwell system are presented. Special interest is devoted to asymptotic regimes where the scales of variation of the electromagnetic field are clearly separated from those associated with the gyromotion of the particles. This volume collects lectures given at the Short Course and Workshop on Kinetic Theory organized at the Fields Institute of Mathematical Sciences in Toronto during the Spring of 2004.
Author: Jacques Lafontaine Publisher: Springer ISBN: 3319207350 Category : Mathematics Languages : en Pages : 408
Book Description
This book is an introduction to differential manifolds. It gives solid preliminaries for more advanced topics: Riemannian manifolds, differential topology, Lie theory. It presupposes little background: the reader is only expected to master basic differential calculus, and a little point-set topology. The book covers the main topics of differential geometry: manifolds, tangent space, vector fields, differential forms, Lie groups, and a few more sophisticated topics such as de Rham cohomology, degree theory and the Gauss-Bonnet theorem for surfaces. Its ambition is to give solid foundations. In particular, the introduction of “abstract” notions such as manifolds or differential forms is motivated via questions and examples from mathematics or theoretical physics. More than 150 exercises, some of them easy and classical, some others more sophisticated, will help the beginner as well as the more expert reader. Solutions are provided for most of them. The book should be of interest to various readers: undergraduate and graduate students for a first contact to differential manifolds, mathematicians from other fields and physicists who wish to acquire some feeling about this beautiful theory. The original French text Introduction aux variétés différentielles has been a best-seller in its category in France for many years. Jacques Lafontaine was successively assistant Professor at Paris Diderot University and Professor at the University of Montpellier, where he is presently emeritus. His main research interests are Riemannian and pseudo-Riemannian geometry, including some aspects of mathematical relativity. Besides his personal research articles, he was involved in several textbooks and research monographs.
Author: K. G. Budden Publisher: Cambridge University Press ISBN: 9780521369527 Category : Science Languages : en Pages : 694
Book Description
This book is concerned with the ionosphere and the magnetosphere, and the theory of their effect on radio waves. It includes accounts of some mathematical topics now widely used in this study, particularly W. K. B. approximations, Airy integral functions and integration by steepest descents. The subject is divided into ray theory and full wave theory. Ray theory is useful for high frequencies when the ionosphere is treated as a horizonally stratified medium. The discussion of the magnetosphere, whose structure is more complicated, includes an account of whistlers and ion cyclotron whistlers. The book has been planned both for final year undergraduates and as a reference book for research. It is suitable as a course book on radio propagation for students of physics or electrical engineering or mathematics. Some of the topics are presented from an elementary viewpoint so as to help undergraduates new to the subject. The later parts are more advanced. Because the subject is so large and has seen many important recent advances, some topics have had to be treated briefly, but there is a full bibliography with about 600 references.
Author: P. M. Banks Publisher: Elsevier ISBN: 1483260666 Category : Science Languages : en Pages : 445
Book Description
Aeronomy, Part A is an attempt to make a comprehensive exposition of the processes in aeronomy, the study of composition, movement, and thermal balance of the upper regions of the planetary atmosphere. The text covers topics such as atmospheric regions and atmospheric density, the temperature and molecular mass of the atmosphere; the permanent constituents and the molecular and isotonic composition of the homosphere; and the transition from the homosphere to the heterosphere. Also covered are topics such as the temperature gradient and energies in the thermosphere, conditions at 200km and above 250km, solar radiation and ionization, and aeronomic reactions. The book is recommended for scientists, especially natural physicists, who would like to know more about the field of aeronomy and its advances.
Author: Sue Blattes Publisher: L'Editeur : EDP Sciences ISBN: 9782868835888 Category : English language Languages : fr Pages : 264
Book Description
Cet ouvrage, devenu célèbre sous son sigle MCSE, a déjà été utilisé par plus de 50 000 étudiants, chercheurs, professionnels. L'objectif est de lire et écrire des textes en anglais scientifique avec facilité et pertinence. L'ouvrage est conçu pour que l'apprenant devienne un véritable utilisateur de l'anglais. La méthode originale repose sur l'analyse des fonctions et structures nécessaires : measurement, frequency, comparison, modification, link words, time, cause and consequence, hypothesis, modality, purpose and process, impersonal forms, compound nouns and adjectives. Dans chaque unit, des tests d'auto-évaluation permettent de se situer et de construire son parcours de formation, d'abord en définissant ses objectifs à l'aide des key points et du lexis, puis, de façon plus personnalisée, en puisant dans les examples in context, checkpoints (back to basics, word web), web search, FAQs... MCSE est l'outil de base d'une méthode qui comprend aussi d'autres outils dans la même collection (Listening Comprehension for Scientiflc English et Speaking Skills in Scientitic English). L'ouvrage est destiné à tout apprenant de niveau baccalauréat qui désire acquérir une réelle compétence dans l'écriture et la lecture de textes en anglais scientifique.
Author: Linda Strande Publisher: IWA Publishing ISBN: 1780404735 Category : Technology & Engineering Languages : en Pages : 428
Book Description
It is estimated that literally billions of residents in urban and peri-urban areas of Africa, Asia, and Latin America are served by onsite sanitation systems (e.g. various types of latrines and septic tanks). Until recently, the management of faecal sludge from these onsite systems has been grossly neglected, partially as a result of them being considered temporary solutions until sewer-based systems could be implemented. However, the perception of onsite or decentralized sanitation technologies for urban areas is gradually changing, and is increasingly being considered as long-term, sustainable options in urban areas, especially in low- and middle-income countries that lack sewer infrastructures. This is the first book dedicated to faecal sludge management. It compiles the current state of knowledge of the rapidly evolving field of faecal sludge management, and presents an integrated approach that includes technology, management, and planning based on Sandecs 20 years of experience in the field. Faecal Sludge Management: Systems Approach for Implementation and Operation addresses the organization of the entire faecal sludge management service chain, from the collection and transport of sludge, and the current state of knowledge of treatment options, to the final end use or disposal of treated sludge. The book also presents important factors to consider when evaluating and upscaling new treatment technology options. The book is designed for undergraduate and graduate students, and engineers and practitioners in the field who have some basic knowledge of environmental and/or wastewater engineering.
Author: Romain Meyrand
Author: CHADI.. SALEM
Author: Charles Vincent
Author: Ahmed Belasri
Author: Thierry Passot
Author: Jacques Lafontaine
Author: K. G. Budden
Author: P. M. Banks
Author: Sue Blattes
Author: Linda Strande