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.




Atomic Radiative Processes


Book Description

Atomic Radiative Processes provides a unified treatment of the theory of atomic radiative processes. Fourier transforms are used to obtain solutions of time-dependent Schrödinger equations, and coupled differential equations are transformed to coupled linear equations that in most cases can be readily solved. This book consists of nine chapters and begins with an overview of some of the properties of the classical field and its interaction with particles, focusing on those aspects needed for a better understanding of quantum theory. The Hamiltonian formalism is used to quantize the field, and the density of states of the radiation field is considered. The following chapters focus on a few Fourier transform techniques and their application to such areas as coherence properties of the field and amplitude and intensity correlations; the theory of angular momentum; the properties of irreducible tensors; quantization of the radiation field; and photon states. The interaction of a two-level atom with single modes of the radiation field is also discussed, along with spontaneous emission and decay processes; the evolution of coupled atomic states; the frequency distribution of emitted radiation; and radiative excitation and fluorescence. This monograph is intended for students and researchers in pure and applied physics.




An Introduction to the Atomic and Radiation Physics of Plasmas


Book Description

Plasmas comprise more than 99% of the observable universe. They are important in many technologies and are key potential sources for fusion power. Atomic and radiation physics is critical for the diagnosis, observation and simulation of astrophysical and laboratory plasmas, and plasma physicists working in a range of areas from astrophysics, magnetic fusion, and inertial fusion utilise atomic and radiation physics to interpret measurements. This text develops the physics of emission, absorption and interaction of light in astrophysics and in laboratory plasmas from first principles using the physics of various fields of study including quantum mechanics, electricity and magnetism, and statistical physics. Linking undergraduate level atomic and radiation physics with the advanced material required for postgraduate study and research, this text adopts a highly pedagogical approach and includes numerous exercises within each chapter for students to reinforce their understanding of the key concepts.




Radiative Processes in Atomic Physics


Book Description

This book offers advanced students and researchers an up-to-date quantum treatment of the interaction of atoms with electromagnetic radiation. Problems and solutions are used to develop concepts, terminology, and the principal results of the quantum theory of radiative processes in atoms. Concepts covered include: radiative transitions between discrete states in atomic systems, atomic photoprocesses involving free particles, coherent phenomena in radiative transitions, extensive treatment of line-broadening mechanisms, atoms in strong fields and theory of angular momentum.




Atomic and Molecular Radiative Processes


Book Description

This book describes selected problems in contemporary spectroscopy in the context of quantum mechanics and statistical physics. It focuses on elementary radiative processes involving atomic particles (atoms, molecules, ions), which include radiative transitions between discrete atomic states, the photoionization of atoms, photorecombination of electrons and ions, bremsstrahlung, photodissociation of molecules, and photoattachment of electrons to atoms. In addition to these processes, the transport of resonant radiation in atomic gases and propagation of infrared radiation in molecular gases are also considered. The book subsequently addresses applied problems such as optical pumping, cooling of gases via laser resonance radiation, light-induced drift of gas atoms, photoresonant plasma, reflection of radio waves from the ionosphere, and detection of submillimeter radiation using Rydberg atoms. Lastly, topical examples in atmospheric and climate change science are presented, such as lightning channel glowing, emission of the solar photosphere, and the greenhouse phenomenon in the atmospheres of the Earth and Venus. Along with researchers, both graduate and undergraduate students in atomic, molecular and atmospheric physics will find this book a useful and timely guide.




Radiative Processes in High Energy Astrophysics


Book Description

This book grew out of the author’s notes from his course on Radiative Processes in High Energy Astrophysics. The course provides fundamental definitions of radiative processes and serves as a brief introduction to Bremsstrahlung and black body emission, relativistic beaming, synchrotron emission and absorption, Compton scattering, synchrotron self-compton emission, pair creation and emission. The final chapter discusses the observed features of Active Galactic Nuclei and their interpretation based on the radiative processes presented in the book. Written in an informal style, this book will guide students through their first encounter with high-energy astrophysics.




Atomic Spectroscopy and Radiative Processes


Book Description

This book describes the basic physical principles of atomic spectroscopy and the absorption and emission of radiation in astrophysical and laboratory plasmas. It summarizes the basics of electromagnetism and thermodynamics and then describes in detail the theory of atomic spectra for complex atoms, with emphasis on astrophysical applications. Both equilibrium and non-equilibrium phenomena in plasmas are considered. The interaction between radiation and matter is described, together with various types of radiation (e.g., cyclotron, synchrotron, bremsstrahlung, Compton). The basic theory of polarization is explained, as is the theory of radiative transfer for astrophysical applications. Atomic Spectroscopy and Radiative Processes bridges the gap between basic books on atomic spectroscopy and the very specialized publications for the advanced researcher: it will provide under- and postgraduates with a clear in-depth description of theoretical aspects, supported by practical examples of applications.




Atomic Radiation and Polymers


Book Description

Atomic Radiation and Polymers examines the effects of radiation on polymer materials. The title deals with chemical changes that took place when polymers are exposed to radiation, and how these changes affect the physical properties of the polymers. The text first covers the interaction of radiation and matter, along with radiation sources and dosimetry. Next, the selection deals with the general properties of long chain polymers. The text also details the organic molecules and irradiated polymers. Chapters 22 to 24 tackle the radiation-induced changes in nuclear chain reaction, while Chapter 25 discusses the irradiation of polymers in solution where both direct and indirect effects occur. The next series of chapters details the theoretical aspects of reactions between the initial acts of ionization or excitation. The last two chapters cover the conductivity change at low radiation intensities, along with the data on radiation damage at very high intensities. The book will be of great interest to researchers and practitioners from the field of nuclear science and polymer technology.




Atom-Photon Interactions


Book Description

Atom-Photon Interactions: Basic Processes and Applications allows the reader to master various aspects of the physics of the interaction between light and matter. It is devoted to the study of the interactions between photons and atoms in atomic and molecular physics, quantum optics, and laser physics. The elementary processes in which photons are emitted, absorbed, scattered, or exchanged between atoms are treated in detail and described using diagrammatic representation. The book presents different theoretical approaches, including: Perturbative methods The resolvent method Use of the master equation The Langevin equation The optical Bloch equations The dressed-atom approach Each method is presented in a self-contained manner so that it may be studied independently. Many applications of these approaches to simple and important physical phenomena are given to illustrate the potential and limitations of each method.




Modern Methods in Collisional-Radiative Modeling of Plasmas


Book Description

This book provides a compact yet comprehensive overview of recent developments in collisional-radiative (CR) modeling of laboratory and astrophysical plasmas. It describes advances across the entire field, from basic considerations of model completeness to validation and verification of CR models to calculation of plasma kinetic characteristics and spectra in diverse plasmas. Various approaches to CR modeling are presented, together with numerous examples of applications. A number of important topics, such as atomic models for CR modeling, atomic data and its availability and quality, radiation transport, non-Maxwellian effects on plasma emission, ionization potential lowering, and verification and validation of CR models, are thoroughly addressed. Strong emphasis is placed on the most recent developments in the field, such as XFEL spectroscopy. Written by leading international research scientists from a number of key laboratories, the book offers a timely summary of the most recent progress in this area. It will be a useful and practical guide for students and experienced researchers working in plasma spectroscopy, spectra simulations, and related fields.