Radiative Processes in Astrophysics


Book Description

Radiative Processes in Astrophysics: This clear, straightforward, and fundamental introduction is designed to present-from a physicist's point of view-radiation processes and their applications to astrophysical phenomena and space science. It covers such topics as radiative transfer theory, relativistic covariance and kinematics, bremsstrahlung radiation, synchrotron radiation, Compton scattering, some plasma effects, and radiative transitions in atoms. Discussion begins with first principles, physically motivating and deriving all results rather than merely presenting finished formulae. However, a reasonably good physics background (introductory quantum mechanics, intermediate electromagnetic theory, special relativity, and some statistical mechanics) is required. Much of this prerequisite material is provided by brief reviews, making the book a self-contained reference for workers in the field as well as the ideal text for senior or first-year graduate students of astronomy, astrophysics, and related physics courses. Radiative Processes in Astrophysics also contains about 75 problems, with solutions, illustrating applications of the material and methods for calculating results. This important and integral section emphasizes physical intuition by presenting important results that are used throughout the main text; it is here that most of the practical astrophysical applications become apparent.




The Magnetic Universe


Book Description

Magnetism is one of the most pervasive features of the Universe, with planets, stars and entire galaxies all having associated magnetic fields. All of these fields are generated by the motion of electrically conducting fluids, the so-called dynamo effect. The precise details of what drives the motion, and indeed what the fluid consists of, differ widely though. In this work the authors draw upon their expertise in geophysical and astrophysical MHD to explore some of these phenomena, and describe the similarities and differences between different magnetized objects. They also explain why magnetic fields are crucial in the formation of the stars, and discuss promising experiments currently being designed to study some of the relevant physics in the laboratory. This interdisciplinary approach makes the book appealing to a wide audience in physics, astrophysics and geophysics.




Solar Magnetic Fields


Book Description

Magnetic fields are responsible for much of the variability and structuring in the universe, but only on the Sun can the basic magnetic field related processes be explored in detail. While several excellent textbooks have established a diagnostic foundation for exploring the physics of unmagnetized stellar atmospheres through spectral analysis, no corresponding treatise for magnetized stellar atmospheres has been available. The present monograph fills this gap. The theoretical foundation for the diagnostics of stellar magnetism is developed from first principles in a comprehensive way, both within the frameworks of classical physics and quantum field theory, together with a presentation of the various solar applications. This textbook can serve as an introduction to solar and stellar magnetism for astronomers and physicists at the graduate or advanced undergraduate level and will also become a resource book for more senior scientists with a general interest in cosmic magnetic fields.




Electromagnetic Processes


Book Description

This book provides an understanding of the theoretical foundations for the calculation of electromagnetic processes. Photon production processes are particularly important in astrophysics, since almost all of our knowledge of distant astronomical objects comes from the detection of radiation from these sources. Further, the conditions therein are extremely varied and a wide variety of naturally occurring electromagnetic phenomena can be described by limiting forms of the basic theory. The first chapter reviews some basic principles that are the underpinnings for a general description of electromagnetic phenomena, such as special relativity and, especially, relativistic covariance. Classical and quantum electrodynamics (QED) are then formulated in the next two chapters, followed by applications to three basic processes (Coulomb scattering, Compton scattering, and bremsstrahlung). These processes are related to other phenomena, such as pair production, and the comparisons are discussed. A unique feature of the book is its thorough discussion of the nonrelativistic limit of QED, which is simpler than the relativistic theory in its formulation and applications. The methods of the relativistic theory are introduced and applied through the use of notions of covariance, to provide a shorter path to the more general theory. The book will be useful for graduate students working in astrophysics and in certain areas of particle physics.




Cosmic Magnetism,


Book Description

The study of extraterrestrial magnetic fields is a relatively new one, confirmation of the existance of the first such field (that of our Sun) having come a s late as 1908. In the past 30 years a great ammount of knowledge has been accumulated on Cosmic Magnetism, which has turned out to be a truly fascinating topic for study. Percy Seymour's book is the first to deal with the topic in a non-mathematical way, and he offers a fine introduction to his subject. The first three chapters consolidate our knowledge on magnetism in general and the magnetic field of the Earth, as well as discussing the reasons for studying astronomy and cosmic magnetism in particular. The remainder of the book is devoted to the main areas of cosmic magnetism - solar, plantetary and interplanetary fields, fields in stars and pulsars, fields of the milky way and fields in other galaxies. Cosmic Magnetism in an ideal book for sixth-formers and undergraduates studying physics or astronomy and will also appeal to amateur astronomers. as previous work on this topic has been 'hidden' in specialised academic journals.




Accretion Processes in Astrophysics


Book Description

It has been more than fifty years since the first significant paper on accretion flows was written. In recent years, X-ray satellites capable of identifying accretion disks and radiation jets - indications that accretion has taken place - have significantly advanced our understanding of these phenomena. This volume presents a comprehensive and up-to-date introduction to the major theoretical and observational topics associated with accretion processes in astrophysics. Comprising lectures presented at the twenty-first Winter School of the Canary Islands Institute of Astrophysics, the text emphasises the physical aspects of accretion, investigating how radiation jets are produced, how accretion power is divided between jets and radiated energy, the geometry of accretion flow, and the accretion processes of active galactic nuclei. Written by an international team of experienced scientists, chapters offer young researchers key analytical tools for supporting and carrying out the next generation of front-line research.




Magnetic Fields of Celestial Bodies


Book Description

Magnetism is one of the basic properties of matter. Mankind has trav elled a long road in discovering and utilizing magnetism, and in this respect the ancient Chinese people have made outstanding contribu tions. In the book 'Lu's Spring and Autumn', written near the end of the Warring States Period, i. e. in the third century B. C. , there is a statement on the "attraction of iron by lodestones". So at that time it was known that magnets can attract ferromagnetic material. At the be ginning ofthe first century A. D. , viz. in the early years ofthe East Hang Dynasty, the famous scholar Wang Chong wrote in his masterpiece 'Len Hen' that the handle of a magnetic dipper pointed to the south. It was thus discovered at the time that magnets can point to the poles of the geomagnetic field. At the beginning of the twelfth century, during the reign of Emperor Hui of the Sung Dynasty, in the two books written by Zhu Yo and Xu Jin, respectively, there are descriptions of the com pass used in navigation. This tells us that the application of compasses was rather widespread at that time. The distinguished scientist Sen Go (1031-1085) discovered the declination of the terrestrial magnetic field. This is four hundred and more years earlier than its discovery by Christopher Columbus in 1492 during his voyage across the Atlantic Ocean. Such facts as these manifest the important contributions of ancient China to global civilization.




Solar and Stellar Magnetic Activity


Book Description

This timely volume provides the first comprehensive review and synthesis of current understanding of magnetic fields in the Sun and similar stars. Magnetic activity results in a wealth of phenomena - including starspots, non-radiatively heated outer atmospheres, activity cycles, deceleration of rotation rates, and even, in close binaries, stellar cannibalism - all of which are covered clearly and authoritatively. This book brings together for the first time recent results in solar studies and stellar studies. The result is an illuminating new view of stellar magnetic activity. Key topics include radiative transfer, convective simulations, dynamo theory, outer-atmospheric heating, stellar winds and angular momentum loss. Researchers are provided with a state-of-the-art review of this exciting field, and the pedagogical style and introductory material make the book an ideal and welcome introduction for graduate students.




Physics of Magnetic Flux Tubes


Book Description

This book presents the physics of magnetic flux tubes, including their fundamental properties and collective phenomena in an ensemble of flux tubes. The physics of magnetic flux tubes is vital for understanding fundamental processes in the solar atmosphere that are shaped and governed by magnetic fields. The concept of magnetic flux tubes is also central to various magnetized media ranging from laboratory plasma and Earth's magnetosphere to planetary, stellar and galactic environments. The book covers both theory and observations. Theoretical models presented in analytical and phenomenological forms that are tailored to practical applications. These are welded together with empirical data extending from the early pioneering observations to the most recent state-of-the-art data. This new edition of the book is updated and contains a significant amount of new material throughout as well as four new chapters and 48 problems with solutions. Most problems make use of original papers containing fundamental results. This way, the original paper, often based on complex theory, turns into a convenient tool for practical use and quantitative analysis.




Numerical Methods in Astrophysics


Book Description

Numerical Methods in Astrophysics: An Introduction outlines various fundamental numerical methods that can solve gravitational dynamics, hydrodynamics, and radiation transport equations. This resource indicates which methods are most suitable for particular problems, demonstrates what the accuracy requirements are in numerical simulations, a