Dynamos

Comprised of lectures for an intensive course held at the Newton Institute in Cambridge, as part of a NATO Advanced Study Institute, the topics covered within this volume include planetary and solar dynamos, fast dynamos, and the use of symmetry principles to derive evolution equations.

Dynamos is a collection of lectures given in July 2007 at the Les Houches Summer School on "Dynamos". Provides a pedagogical introduction to topics in Dynamos Addresses each topic from the basis to the most recent developments Covers the lectures by internationally-renowned and leading experts

Nonlinear dynamo theory is central to understanding the magnetic structures of planets, stars and galaxies. In chapters contributed by some of the leading scientists in the field, this text explores some of the recent advances in the field. Both kinetic and dynamic approaches to the subject are considered, including fast dynamos, topological methods in dynamo theory, physics of the solar cycle and the fundamentals of mean field dynamo. Advances in Nonlinear Dynamos is ideal for graduate students and researchers in theoretical astrophysics and applied mathematics, particularly those interested in cosmic magnetism and related topics, such as turbulence, convection, and more general nonlinear physics.

Although the origin of Earth's and other celestial bodies' magnetic fields remains unknown, we do know that the motion of electrically conducting fluids generates and maintains these fields, forming the basis of magnetohydrodynamics (MHD) and, to a larger extent, dynamo theory. Answering the need for a comprehensive, interdisciplinary introduction to this area, Mathematical Aspects of Natural Dynamos provides a foundation in dynamo theory before moving on to modeling aspects of natural dynamos. Bringing together eminent international contributors, the book first introduces governing equations, outlines the kinematic dynamo theory, covers nonlinear effects, including amplitude saturation and polarity reversals, and discusses fluid dynamics. After establishing this base, the book describes the Earth's magnetic field and the current understanding of its characteristics. Subsequent chapters examine other planets in our solar system and the magnetic field of stars, including the sun. The book also addresses dynamo action on the large scale of galaxies, presents modeling experiments of natural dynamos, and speculates about future research directions. After reading this well-illustrated, thorough, and unified exploration, you will be well prepared to embark on your own journey through this fascinating area of research.

This is a handy companion guide for anybody interested in making, running small dynamos and electrical motors.

Exploring the origins and evolution of magnetic fields in planets, stars and galaxies, this book gives a basic introduction to magnetohydrodynamics and surveys the observational data, with particular focus on geomagnetism and solar magnetism. Pioneering laboratory experiments that seek to replicate particular aspects of fluid dynamo action are also described. The authors provide a complete treatment of laminar dynamo theory, and of the mean-field electrodynamics that incorporates the effects of random waves and turbulence. Both dynamo theory and its counterpart, the theory of magnetic relaxation, are covered. Topological constraints associated with conservation of magnetic helicity are thoroughly explored and major challenges are addressed in areas such as fast-dynamo theory, accretion-disc dynamo theory and the theory of magnetostrophic turbulence. The book is aimed at graduate-level students in mathematics, physics, Earth sciences and astrophysics, and will be a valuable resource for researchers at all levels.

Does your imaginative, computer-proficient daughter tune out in the classroom? Does your spirited son become headstrong and aggressive when faced with the simplest decisions? Does your bold, energetic child have trouble focusing on basic tasks? Millions of children--one in five--have what psychologist Lucy Jo Palladino, Ph.D., calls the Edison trait: dazzling intelligence, an active imagination, a free-spirited approach to life, and the ability to drive everyone around them crazy. Named after Thomas Edison--who flunked out of school only to harness his talents and give the world some of its finest inventions--the Edison trait is on the rise in our younger generation. The heart of the issue is that they think divergently--they overflow with many ideas--while schools, organized activities, and routines of daily living reward convergent thinking, which focuses on one idea at a time. Drawing on examples from more than two decades of private practice, Dr. Palladino helps us cope with this challenging aspect of our child's intellect and personality, explaining in clear terms: - The three Edison-trait personality types: dreamers, discoverers, and dynamos - The eight steps to understanding, reaching, and teaching your Edison-trait child - The connection between the Edison trait and A.D.D.

Astrophysical dynamos are at the heart of cosmic magnetic fields of a wide range of scales, from planets and stars to entire galaxies. This book presents a thorough, step-by-step introduction to solar and stellar dynamos. Looking first at the ultimate origin of cosmic seed magnetic fields, the antagonists of field amplification are next considered: resistive decay, flux expulsion, and flows ruled out by anti-dynamo theorems. Two kinematic flows that can act as dynamos are then studied: the Roberts cell and the CP-flow. Mean-field electrodynamics and derivation of the mean-field dynamo equations lead to the alpha Omega-dynamo, the flux transport dynamo, and dynamos based on the Babcock-Leighton mechanism. Alternatives to the mean-field theory are also presented, as are global MHD dynamo simulations. Fluctuations and grand minima in the solar cycle are discussed in terms of dynamo modulations through stochastic forcing and nonlinear effects. The book concludes with an overview of the major challenges in understanding stellar magnetic fields and their evolution in terms of various dynamo models, global MHD simulations, and fossil fields. Each chapter is accompanied by an annotated bibliography, guiding the readers to the relevant technical literature, which may lead them to carry out their own research in the field of dynamo theory.

The increasing power of computer resources along with great improvements in observational data in recent years have led to some remarkable and rapid advances in astrophysical fluid dynamics. The subject spans three distinct but overlapping communities whose interests focus on (1) accretion discs and high-energy astrophysics; (2) solar, stellar, and galactic magnetic fields; and (3) the geodynamo, planetary magnetic fields, and associated experiments. This book grew out of a special conference sponsored by the London Mathematical Society with the support of EPSRC that brought together leading researchers in all of these areas to exchange ideas and review the status of the field. The many interesting problems addressed in this volume concern:

It is well established and appreciated by now that more than 99% of the baryonic matter in the universe is in the plasma state. Most astrophysical systems could be approximated as conducting fluids in a gravitational field. It is the combined effect of these two that gives rise to the mind boggling variety of configurations in the form of filaments, loops, jets and arches. The plasma structures that cannot last for more than a second or less in a laboratory remain intact for astronomical time and spatial scales in an astrophysical setting. The case in point is the well known extragalactic jets whose collimation and stability has remained an enigma inspite of the efforts of many for many long years. The high energy radiation sources such as the active galactic nuclei again summon the coherent plasma radiation processes for their exceptionally large output from regions of relatively small physical sizes. The generation of magnetic field, anomalous transport of angular momentum with decisive bearing on star formation processes, the ubiquitous MHD turbulence under conditions irreproducible in terrestrial laboratories are some of the generic issues still awaiting a concerted effort for their understanding. Quantum Plasmas, pair plasmas and pair-ion plasmas exist under extreme conditions in planetary interiors and exotic stars. In this workshop plasma physicists, astrophysicists and plasma astrophysicists are brought together to discuss these issues.

This practical engineering handbook is in its complete and unabridged original form, extensively illustrated and full of instruction that is as useful and practical today as it was when originally published. Contents include - How A Dynamo Works, General Considerations - Simple Cycle-Lighting Dynamo - Hand-Driven 20-Watt Dynamo - Two Minature Dynamos - Direct-Coupled Dynamo And Water Motor - Three Small Electric Motors - 6-Volt Traction Motor - 60-Watt Simplex Dynamo Or Motor - Winding Data - Faults And Remedies - Various Dynamos And Motors. Many of the earliest books, particularly those dating back to the 1900s and before, are now extremely scarce and increasingly expensive. We are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.

Artistic Dynamos: An Ethnography on Music in Central African Kingdoms uses stories and research from Ngiemboon communities of West Cameroon as touchstones for proposing new approaches to arts scholarship and community development. Building on the results of ethnographic research, artistic action is viewed through the lens of communication. This view brings a picture of increased cultural energy in the enactment of artistic genres—melodic, rhythmic, poetic, dramatic, visual, and performative. Schrag’s treatise will change how scholars across disciplines understand and engage with the arts. This volume offers methods for improved scholarship, resulting in communities living better lives. The author’s website contains the video and audio recordings discussed in the book, plus full-color versions of many photos and diagrams. www.ArtisticDynamos.com

Depicts the careers of 32 young American business people and examines the reasons for their successes