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.

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.

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.

Helioseismology has enabled us to probe the internal structure and dynamics of the Sun, including how its rotation varies in the solar interior. The unexpected discovery of an abrupt transition - the tachocline - between the differentially rotating convection zone and the uniformly rotating radiative interior has generated considerable interest and raised many fundamental issues. This volume contains invited reviews from distinguished speakers at the first meeting devoted to the tachocline, held at the Isaac Newton Institute. It provides a comprehensive account of the understanding of the properties and dynamics of the tachocline, including both observational results and major theoretical issues, involving both hydrodynamic and magnetohydrodynamic behaviour. The Solar Tachocline is a valuable reference for researchers and graduate students in astrophysics, heliospheric physics and geophysics, and the dynamics of fluids and plasmas.

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.

The Sun as a Guide to Stellar Physics illustrates the significance of the Sun in understanding stars through anexamination of the discoveries and insights gained from solar physics research. Ranging from theories to modelingand from numerical simulations to instrumentation and data processing, the book provides an overview of whatwe currently understand and how the Sun can be a model for gaining further knowledge about stellar physics.Providing both updates on recent developments in solar physics and applications to stellar physics, this bookstrengthens the solar–stellar connection and summarizes what we know about the Sun for the stellar, space, andgeophysics communities. - Applies observations, theoretical understanding, modeling capabilities and physical processes first revealed by the sun to the study of stellar physics - Illustrates how studies of Proxima Solaris have led to progress in space science, stellar physics and related fields - Uses characteristics of solar phenomena as a guide for understanding the physics of stars

This volume provides a comprehensive overview of the current understanding of the dynamo processes that generate magnetic fields in the Sun and other stars with outer convection zones. Magnetic fields are responsible for the restless activity of the Sun, which include the coming and going of sunspots throughout its 11-year activity cycle, the heating of the solar corona, and the driving forces behind huge eruptions of mass and energy that can affect near-Earth space and terrestrial technical systems. Likewise, other stars show such activity, often even much more energetically as their solar counterparts. The review papers collected in this volume are written by experts in this research field. The papers deliver introductions to the observational results on solar and stellar magnetic fields and provide detailed presentations on the theoretical concepts and models for self-excited dynamo processes and the underlying flow patterns that cause the emergence, structure, and evolution of magnetic patterns at the surfaces of the Sun and other stars. Comprehensive and realistic numerical simulations have become an indispensable tool for understanding the turbulent processes in stellar interiors as well as for testing analytical approaches and simplified models. Readers looking for a comprehensive and up-to-date account of this dynamic research field will find a most valuable collection of reviews; serving both as an introduction for newcomers in the field as well as a timely compendium for the active researcher. The book is a spin-off from the Topical Collection "Solar and Stellar Dynamos: A New Era" of the journal Space Science Reviews.