This volume surveys our current scientific understanding of the terrestrial aurora. It is organized into eleven reviews detailing theoretical and observational aspects of characteristic auroral morphologies, and how these in turn are organized according to local time, latitude, and activity level. Popular descriptions often attribute the aurora to the interaction of charged particles from the solar wind with atoms in the upper atmosphere. In fact, most auroras are not the result of direct entry of solar wind particles. Rather, as detailed in this volume, auroral particle acceleration and generation of auroral forms occur primarily within the magnetosphere. Importantly, many key aspects of the aurora – most notably, the physical mechanisms responsible for the generation of discrete arcs – are still unexplained, and auroral physics continues to be an active area of scientific research. Each review chapter therefore includes a summary of open questions for further investigation. Providing the first comprehensive review of the terrestrial aurora in two decades, this book will aid both active researchers and newcomers interested in understanding the current state of the field. Previously published Space Science Reviews in the Topical Collection "Auroral Physics”

This volume gives a broad synthesis of the current knowledge and understanding of the plasma physics behind the aurora. The aurora is not only one of the most spectacular natural phenomena on Earth, but the underlying physical processes are expected to be ubiquitous in the plasma universe. Recognizing the enormous progress made over the last decade) through in situ and groundbased measurements as well as theoretical modelling, it seemed timely to write the first comprehensive and integrated book on the subject. Recent advances concern the clarification of the nature of the acceleration process of the electrons that are responsible for the visible aurora, the recognition of the fundamental role of the large-scale current systems in organizing the auroral morphology, and of the interplay between particles and electromagnetic fields.

This volume surveys our current scientific understanding of the terrestrial aurora. It is organized into eleven reviews detailing theoretical and observational aspects of characteristic auroral morphologies, and how these in turn are organized according to local time, latitude, and activity level. Popular descriptions often attribute the aurora to the interaction of charged particles from the solar wind with atoms in the upper atmosphere. In fact, most auroras are not the result of direct entry of solar wind particles. Rather, as detailed in this volume, auroral particle acceleration and generation of auroral forms occur primarily within the magnetosphere. Importantly, many key aspects of the aurora – most notably, the physical mechanisms responsible for the generation of discrete arcs – are still unexplained, and auroral physics continues to be an active area of scientific research. Each review chapter therefore includes a summary of open questions for further investigation. Providing the first comprehensive review of the terrestrial aurora in two decades, this book will aid both active researchers and newcomers interested in understanding the current state of the field. Previously published Space Science Reviews in the Topical Collection "Auroral Physics”

Auroral physics is a subject that has seen considerable change and development over the past twenty years, particularly because of its importance to space research and the exploration of the near earth environment. In July 1988, a conference held at St. Johns College, Cambridge, celebrated the centenary of Sydney Chapman, the founder of the subject in its modern form, and brought together an international group of experts in the field to discuss important developments and the likely directions of future research. Auroral Physics gives a comprehensive overview of the subject, and puts forward some important new ideas.

This book describes the history of the progress made in auroral science and magnetospheric physics by providing examples of ideas, controversies, struggles, acceptance, and success in some instances. The author, a distinguished auroral scientist, fully describes his experiences in characterizing and explaining auroral phenomena. The volume also includes beautiful full-color photos of the aurora.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 197. Many of the most basic aspects of the aurora remain unexplained. While in the past terrestrial and planetary auroras have been largely treated in separate books, Auroral Phenomenology and Magnetospheric Processes: Earth and Other Planets takes a holistic approach, treating the aurora as a fundamental process and discussing the phenomenology, physics, and relationship with the respective planetary magnetospheres in one volume. While there are some behaviors common in auroras of the different planets, there are also striking differences that test our basic understanding of auroral processes. The objective, upon which this monograph is focused, is to connect our knowledge of auroral morphology to the physical processes in the magnetosphere that power and structure discrete and diffuse auroras. Understanding this connection will result in a more complete explanation of the aurora and also further the goal of being able to interpret the global auroral distributions as a dynamic map of the magnetosphere. The volume synthesizes five major areas: auroral phenomenology, aurora and ionospheric electrodynamics, discrete auroral acceleration, aurora and magnetospheric dynamics, and comparative planetary aurora. Covering the recent advances in observations, simulation, and theory, this book will serve a broad community of scientists, including graduate students, studying auroras at Mars, Earth, Saturn, and Jupiter. Projected beyond our solar system, it may also be of interest for astronomers who are looking for aurora-active exoplanets.

International Geophysics Series, Volume 2: Physics of the Aurora and Airglow explores certain physical aspects of aurora and airglow. This volume is composed of 13 chapters and begins with surveys of the theory and spectroscopic and photometric analyses of radiation from the upper atmosphere. The subsequent chapters treat the geographic distribution of aurora and its physical processes in the atmosphere. Other chapters examine the theory of hydrogen emission in aurora, resonance scattering by atmospheric sodium, the excitation of the oxygen red lines in the airglow, and an atlas of the auroral spectrum. A chapter focuses on the analysis of twilight observations for emission heights. The concluding chapters discuss the theory of day airglow, as well as the spectral photometry and excitation of the nightglow. This book is of value to geophysicists, theoreticians, and scientists of the allied fields of geophysics.

The aim of this book is to describe and discuss the aurora as an optical phenomenon, one which can be observed by the naked eye as well as with more sensitive optical detectors. It continues the tradition of study ing that impressive and imaginative play of nature, the northern lights, seen and discussed by the Greek philosphers as early as the sixth century B.c. Today the study of the optical aurora is only one of many ways of acquiring information about a major phenomenon: the ejection of plasma from the sun, the interaction of this plasma with the geomagnetic field and the injection of fast particles into the earth's atmosphere. of the optical aurora is justified by the Hence, the separate treatment particular scientific approach: detection and interpretation of electro magnetic radiation, approximately in the 1000-100000 A region, produc ed through interaction between the auroral particles and the earth's atmosphere. Other techniques, such as radio observations, X-ray observations, direct particle detections from rockets and satellites, studies of magnetic storms, and measurements of the magnetic field and plasma properties in the magnetosphere, are as important or more important than the classical way of studying the optical aurora. Nevertheless, it was felt worthwhile to treat the optical aurora in a separate book, perhaps mainly because today one author cannot master the whole subject with sufficient competence. This book is thus one volume in a series of books giving a more complete picture of physics and chemistry in space.

Over the past two decades auroral science has developed from a somewhat mysterious and imprecise specialty into a discipline central in the study of the ionosphere and magnetosphere. The investigation of aurora unites scientists with very different backgrounds and interests so that it is difficult to write a self-contained account of the field in a book of reasonable length. In this work I have attempted to include those aspects of theory which I have found valuable in predicting the effects on the atmosphere of auroral particle precipitation. In addition I have attempted to describe the techniques of observation with particular emphasis on optical methods which have been useful. While the aeronomy of aurora has been regarded as central, the mechanisms by which particles are accelerated and precipitated into the atmosphere is of no less interest. This aspect of the subject has however been treated in a briefer fashion since it is a part of the immense and rapidly developing field of magnetospheric science. Generally I have attempted to provide a coherent introduction to auroral science with an emphasis on relatively simple physical interpretations and models. References are given to enable the reader to find more extensive or rigorous discussions of particular topics. A fairly complete, quantitative atlas of the auroral spectrum is included.