Download or read book Mod lisation et contr le hamiltonien du transport radial dans les plasmas magn tis s configuration lin aire written by Olivier Izacard and published by . This book was released on 2011 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dans l'optique de produire de l'énergie à travers les réactions de fusion, nous sommes amenés à étudier des phénomènes physiques qui ont lieux dans les tokamaks. Les instabilités qui existent dans les tokamaks peuvent fortement dégrader le confinement et ont un impacte sur le fonctionnement de futurs réactions à fusion. Des mesures révèlent un fort transport radial. Même si ce transport radial est en partie est une conséquence des collisions, l'instabilité d'interchange est la source dominante à ce transport puisque le type de plasmas nous intéressant sont faiblement collisionnels. Dans la limite non collisionnelle, la description hamiltonienne permet de décrire le système dynamique des particules du plasmas dans un champ électromagnétique. Nous donnons de l'importance à cette description afin de pouvoir accéder aux outils hamiltoniens.Nous travaillons sur la modélisation et le contrôle hamiltonien du transport radial. Après avoir écrit le modèle hamiltonien des particules d'un plasma magnétisé, nous introduisons les réductions de ce modèle lagrangien en modèles eulériens réduits afin de s'adapter à certains calculs numériques et théoriques. Ces réductions donnent lieux aux équations fluides hamiltonien. Cependant, nous montrons que ces réductions peuvent faire perdre la propriété hamiltonienne. En particulier pour obtenir un modèle ayant la température des ions (puisqu'elle n'est pas négligeable au centre du plasma), nous montrons la procédure conservant la propriété hamiltonienne à partir du modèle sans température des ions.Quant à l'étude du transport radial, nous appliquons une des propriétés hamiltoniennes (le contrôle) afin de créer une barrière de transport par des perturbations du système. Nous étudions de manière idéale l'effet du contrôle à travers la dynamique lagrangienne des traceurs appelés particules test. Nous faisons particulièrement des efforts dans la prise en compte des contraintes numériques et expérimentales. Nous montrons notamment la robustesse du contrôle lors de l'application des perturbations par des sondes de Langmuir.Finalement, nous étudions l'application du contrôle dans un modèle eulérien décrivant la rétroaction du plasmas (à travers la densité et le potentiel électrique) lorsque nous appliquons les perturbations. Cette étape permet de prendre en compte le couplage du système plasma-perturbations. En utilisant un code fluide permettant de décrire le plasma de bord lors de perturbations générées par des sondes de Langmuir. Nous développons un algorithme permettant de calculer le contrôle en tout temps en fonction du potentiel électrique. Nous montrons alors que la valeur moyenne du potentiel électrique joue un rôle important pour l'application du contrôle dans un modèle fluide.
Download or read book Self Organization of Hot Plasmas written by Yu.N. Dnestrovskij and published by Springer. This book was released on 2014-07-08 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this monograph the author presents the Canonical Profile Transport Model or CPTM as a rather general mathematical framework to simulate plasma discharges. The description of hot plasmas in a magnetic fusion device is a very challenging task and many plasma properties still lack a physical explanation. One important property is plasma self-organization. It is very well known from experiments that the radial profile of the plasma pressure and temperature remains rather unaffected by changes of the deposited power or plasma density. The attractiveness of the CPTM is that it includes the effect of self-organization in the mathematical model without having to recur to particular physical mechanisms. The CPTM model contains one dimensional transport equations for ion and electron temperatures, plasma density and toroidal rotation velocity. These equations are well established and in fact are essentially a reformulation the laws of energy, particle and momentum conservation. But the expressions for the energy and particle fluxes, including certain critical gradients, are new. These critical gradients can be determined using the concept of canonical profiles for the first time formulated in great detail in the book. This concept represents a totally new approach to the description of transport in plasmas. Mathematically, the canonical profiles are formulated as a variational problem. To describe the temporal evolution of the plasma profiles, the Euler equation defining the canonical profiles is solved together with the transport equations at each time step. The author shows that in this way it is possible to describe very different operational scenarios in tokamaks (L-Mode, H-Mode, Advanced Modes, Radiating Improved Modes etc...), using one unique principle. The author illustrates the application of this principle to the simulation of plasmas on leading tokamak devices in the world (JET, MAST, T-10, DIII-D, ASDEX-U, JT-60U). In all cases the small differences between the calculated profiles for the ion and electron temperatures and the experimental is rather confirm the validity of the CPTM. In addition, the model also describes the temperature and density pedestals in the H-mode and non steady-state regimes with current and density ramp up. The proposed model therefore provides a very useful mathematical tool for the analysis of experimental results and for the prediction of plasma parameters in future experiments.
Download or read book A New Modelling of the Cross field Transport in Diverted Edge Plasma written by Serafina Baschetti and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Le fonctionnement à l'équilibre du réacteur à fusion de prochaine génération, ITER, nécessitera le développement d'outils numériques fiables permettant d'estimer les paramètres d'ingénierie clés à un coût de calcul raisonnable. Les codes de transport répondent à cette exigence car ils reposent sur des équations fluides bidimensionnelles qui sont moyennées sur les fluctuations temporelles, de la même manière que les modèles « Reynolds Averaged Navier-Stokes » couramment utilisés dans la communauté des fluides neutres. De plus, les codes de transport peuvent rassembler la plupart des ingrédients physiques régissant le comportement du plasma de bord, ainsi que une topologie magnétique réaliste et la géométrie du mur. Cependant, leur prévisibilité est limitée par une description inadéquate des flux turbulents perpendiculaires aux lignes de champ magnétique, qui influent fortement e confinement du plasma sur de longues périodes. En effet les flux perpendiculaires, supposés diffusifs, sont grossièrement déterminés par des coefficients de diffusion homogènes ou "ad-hoc", ou par des procédures à boucle de rétroaction appliquées "a-posteriori" à des données expérimentales. Motivés par ces questions, nous présentons dans ce travail un nouveau modèle pour estimer de manière cohérente la distribution des flux perpendiculaires dans les codes de transport, lorsque les plasmas en régime permanent sont concernés. La stratégie consiste à introduire des outils numériques efficaces largement utilisés dans la communauté de la turbulence neutre en physique des plasmas. Deux concepts clés sont inspirants dans la communauté des fluides neutres. Le premier est "l'hypothèse de Boussinesq". Elle consiste à linéariser le tenseur de contraintes de Reynolds dansl'équation de Navier-Stokes moyennée dans le temps via une relation de diffusion dans laquelle le terme de proportionnalité est appelé « eddy viscosity ». Le deuxième concept est le modèle "k-epsilon", dans lequel les équations de transport pour l'énergie turbulente cinétique moyenne et le taux d'échange d'énergie entre les structures turbulentes sont conçues de manière semi-empirique. A l'équilibre, k et epsilon permettent une estimation auto-cohérente de l'« eddy viscosity », intégrant ainsi l'impact de la turbulence sur les flux moyennés à l'état d'équilibre. Ces concepts ne peuvent pas être appliqués directement pour enrichir la modélisation des flux perpendiculaires dans les plasmas en raison de différentes propriétés de turbulence. Par conséquent, nous suggérons une adaptation du modèle k-epsilon pour les flux neutres à des plasmas à confinement magnétique, où deux équations de transport pour l'énergie cinétique turbulente et son taux de dissipation sont dérivées algébriquement, y compris la physique de l'instabilité d'interchange linéaire, responsable de la distribution "ballonnée" du transport perpendiculaire dans le bord du plasma. Différentes approches sont décrites pour fermer les paramètres libres : premièrement, une procédure de boucle de rétroaction pour optimiser les résultats numériques comparés avec un test expérimental. Ensuite, on assume une loi d'échelle de référence pour la largeur du profil de flux de chaleur dans la SOL, déterminée empiriquement à partir des mesures expérimentales du flux de chaleur sur le divertor externe dans diverses machines. Le nouveau modèle est intégré au package de transport SolEdge2D-EIRENE, développé en collaboration entre le CEA et le laboratoire M2P2 de l'Université d'Aix-Marseille. Les résultats numériques à l'état d'équilibre sont discutés et on démontre qu'ils se comparent favorablement aux données expérimentales soit à l'outer midplane que au divertor externe. De plus, on montre que les distributions de diffusivité présentent des asymétries poloïdales cohérentes avec la distribution "ballonnée" du transport perpendiculaire observée dans les mêmes conditions dans les codes de premier principe et les expériences.
Download or read book Magnetic Heterostructures written by H. Zabel and published by Springer. This book was released on 2007-10-26 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterostructures consist of combinations of different materials, which are in contact through at least one interface. Magnetic heterostructures combine different physical properties which do not exist in nature. This book provides the first comprehensive overview of an exciting and fast developing field of research, which has already resulted in numerous applications and is the basis for future spintronic devices.
Download or read book Hyperbolic Problems written by American Institute of Mathematical Sciences and published by . This book was released on 2014 with total page 1069 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Science and Application of Nanotubes written by D. Tománek and published by Springer Science & Business Media. This book was released on 2005-12-17 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series of books, which is published at the rate of about one per year, addresses fundamental problems in materials science. The contents cover a broad range of topics from small clusters of atoms to engineering materials and involve chemistry, physics, materials science, and engineering, with length scales ranging from Ångstroms up to millimeters. The emphasis is on basic science rather than on applications. Each book focuses on a single area of current interest and brings together leading experts to give an up-to-date discussion of their work and the work of others. Each article contains enough references that the interested reader can access the relevant literature. Thanks are given to the Center for Fundamental Materials Research at Michigan State University for supporting this series. M. F. Thorpe, Series Editor E-mail: thorpe@pa. msu. edu East Lansing, Michigan V PREFACE It is hard to believe that not quite ten years ago, namely in 1991, nanotubes of carbon were discovered by Sumio Iijima in deposits on the electrodes of the same carbon arc apparatus that was used to produce fullerenes such as the “buckyball”. Nanotubes of carbon or other materials, consisting ofhollow cylinders that are only a few nanometers in diameter, yet up to millimeters long, are amazing structures that self-assemble under extreme conditions. Their quasi-one-dimensional character and virtual absence of atomic defects give rise to a plethora of unusual phenomena.
Download or read book Medicinal Chemistry written by Thomas Nogrady and published by Oxford University Press. This book was released on 2005-08-11 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fully updated and rewritten by a basic scientist who is also a practicing physician, the third edition of this popular textbook remains comprehensive, authoritative and readable. Taking a receptor-based, target-centered approach, it presents the concepts central to the study of drug action in a logical, mechanistic way grounded on molecular and principles. Students of pharmacy, chemistry and pharmacology, as well as researchers interested in a better understanding of drug design, will find this book an invaluable resource. Starting with an overview of basic principles, Medicinal Chemistry examines the properties of drug molecules, the characteristics of drug receptors, and the nature of drug-receptor interactions. Then it systematically examines the various families of receptors involved in human disease and drug design. The first three classes of receptors are related to endogenous molecules: neurotransmitters, hormones and immunomodulators. Next, receptors associated with cellular organelles (mitochondria, cell nucleus), endogenous macromolecules (membrane proteins, cytoplasmic enzymes) and pathogens (viruses, bacteria) are examined. Through this evaluation of receptors, all the main types of human disease and all major categories of drugs are considered. There have been many changes in the third edition, including a new chapter on the immune system. Because of their increasingly prominent role in drug discovery, molecular modeling techniques, high throughput screening, neuropharmacology and genetics/genomics are given much more attention. The chapter on hormonal therapies has been thoroughly updated and re-organized. Emerging enzyme targets in drug design (e.g. kinases, caspases) are discussed, and recent information on voltage-gated and ligand-gated ion channels has been incorporated. The sections on antihypertensive, antiviral, antibacterial, anti-inflammatory, antiarrhythmic, and anticancer drugs, as well as treatments for hyperlipidemia and peptic ulcer, have been substantially expanded. One new feature will enhance the book's appeal to all readers: clinical-molecular interface sections that facilitate understanding of the treatment of human disease at a molecular level.
Download or read book Silicon written by Paul Siffert and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: With topics ranging from epitaxy through lattice defects and doping to quantum computation, this book provides a personalized survey of the development and use of silicon, the basis for the revolutionary changes in our lives sometimes called "The Silicon Age." Beginning with the very first developments more than 50 years ago, this reports on all aspects of silicon and silicon technology up to its use in exciting new technologies, including a glance at possible future developments.
Download or read book Strongly Coupled Plasma Physics written by Forrest J. Rogers and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt: A NATO Advanced Research Workshop on Strongly Coupled Plasma Physics was held on the Santa Cruz Campus of the University of California, from August 4 through August 9, 1986. It was attended by 80 participants from 13 countries, 45 of whom were invited speakers. The present volume contains the texts of the invited talks and many of the contributed papers. The relative length of each text is roughly proportional to the length of the workshop presentation. The aim of the workshop was to bring together leading researchers from a number of related disciplines in which strong Coulomb interactions play a dominant role. Compared to the 1977 meeting in Orleans-la-Source, France and the 1982 meeting in Les-Houches, France, it is apparent that the field of strongly coupled plasmas has expanded greatly and has become a very significant field of physics with a wide range of applications. This workshop had a far greater participation of experimental researchers than did the previous two, and some confrontations of real experiments with theoretical calculations occurred. In the two earlier meetings the theoretical presentations were dominated by numerical simulations of static and dynamic properties of various strongly coupled plasmas. The dearth of experiments in the 1970's is now replaced by some very good experimental efforts.
Download or read book Advanced Intelligent Systems for Sustainable Development AI2SD 2020 written by Janusz Kacprzyk and published by Springer Nature. This book was released on 2022-02-10 with total page 1298 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book publishes the best papers accepted and presented at the 3rd edition of the International Conference on Advanced Intelligent Systems for Sustainable Development Applied to Agriculture, Energy, Health, Environment, Industry, Education, Economy, and Security (AI2SD’2020). This conference is one of the biggest amalgamations of eminent researchers, students, and delegates from both academia and industry where the collaborators have an interactive access to emerging technology and approaches globally. In this book, readers find the latest ideas addressing technological issues relevant to all areas of the social and human sciences for sustainable development. Due to the nature of the conference with its focus on innovative ideas and developments, the book provides the ideal scientific and brings together very high-quality chapters written by eminent researchers from different disciplines, to discover the most recent developments in scientific research.
Download or read book Singular Optics written by Gregory J. Gbur and published by CRC Press. This book was released on 2016-11-17 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This engagingly written text provides a useful pedagogical introduction to an extensive class of geometrical phenomena in the optics of polarization and phase, including simple explanations of much of the underlying mathematics." —Michael Berry, University of Bristol, UK "The author covers a vast number of topics in great detail, with a unifying mathematical treatment. It will be a useful reference for both beginners and experts...." —Enrique Galvez, Charles A. Dana Professor of Physics and Astronomy, Colgate University "a firm and comprehensive grounding both for those looking to acquaint themselves with the field and those of us that need reminding of the things we thought we knew, but hitherto did not understand: an essential point of reference." —Miles Padgett, Kelvin Chair of Natural Philosophy and Vice Principal (Research), University of Glasgow This book focuses on the various forms of wavefield singularities, including optical vortices and polarization singularities, as well as orbital angular momentum and associated applications. It highlights how an understanding of singular optics provides a completely different way to look at light. Whereas traditional optics focuses on the shape and structure of the non-zero portions of the wavefield, singular optics describes a wave’s properties from its null regions. The contents cover the three main areas of the field: the study of generic features of wavefields, determination of unusual properties of vortices and wavefields that contain singularities, and practical applications of vortices and other singularities.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1988 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Intelligent Systems for Sustainable Development AI2SD 2018 written by Mostafa Ezziyyani and published by Springer. This book was released on 2019-02-13 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers papers presented at the International Conference on Advanced Intelligent Systems for Sustainable Development (AI2SD-2018), which was held in Tangiers, Morocco on 12–14 July 2018. It highlights how advanced intelligent systems have successfully been used to develop tools and techniques for modeling, prediction and decision support in connection with the environment. Though chiefly intended for researchers and practitioners in advanced intelligent systems for sustainable development, the book will also be of interest to those working in environment and the Internet of Things, environment and big data analysis, summarization, prediction, remote sensing & geo-information, geophysics, marine and coastal environments, and sensor networks for environment services.
Download or read book Evolution of the Solar System written by Hannes Alfvén and published by . This book was released on 1976 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Emergence of Complexity in Mathematics Physics Chemistry and Biology written by Bernard Pullman and published by Princeton University Press. This book was released on 1996 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this volume, some of the world's leading scientists discuss the role of complexity across all the scientific disciplines. Opinions differ: for some, complexity holds the key to a deeper and fuller understanding of the world; to others, it is merely a modern version of the philsophers' stone.
Download or read book Concentrator Location in Telecommunications Networks written by Hande Yaman and published by Springer. This book was released on 2008-11-01 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the only recent title to present polyhedral results and exact solution methods for location problems encountered in telecommunications, but which also have applications in other areas, such as transportation and supply chain management.
Download or read book Computational Materials Design written by Tetsuya Saito and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of ten chapters which outline a wide range of technologies from first-principle calculations to continuum mechanics, with applications to materials design and development. Written with a clear exposition, this book will be invaluable for engineers who want to learn about the modern technologies and techniques utilized in materials design.
