The Earth's Magnetic Field : Its History, Origin, and Planetary Perspective

This volume provides comprehensive and authoritative coverage of all the main areas linked to geomagnetic field observation, from instrumentation to methodology, on ground or near-Earth. Efforts are also focused on a 21st century e-Science approach to open access to all geomagnetic data, but also to the data preservation, data discovery, data rescue, and capacity building. Finally, modeling magnetic fields with different internal origins, with their variation in space and time, is an attempt to draw together into one place the traditional work in producing models as IGRF or describing the magnetic anomalies.

This 1998 book documents the collection, processing and analysis of satellite magnetic field data.

The purpose of this paper is to introduce the reader to the active sun as a source of disturbance that affect the magnetic field measured at the earth's surface. Included under this topic are the general sun's properties, solar surface activity centers and characteristics of the solar field and ejecta flowing into interplanetary space.

Consisting of more than 150 articles written by leading experts, this authoritative reference encompasses the entire field of solid-earth geophysics. It describes in detail the state of current knowledge, including advanced instrumentation and techniques, and focuses on important areas of exploration geophysics. It also offers clear and complete coverage of seismology, geodesy, gravimetry, magnetotellurics and related areas in the adjacent disciplines of physics, geology, oceanography and space science.

Topics involved in studies of the Earth's magnetic field and its secular variation range from the intricate observations of geomagnetism, to worldwide studies of archeomagnetism and paleomagnetism, through to the complex mathematics of dynamo theory. Traditionally these different aspects of geomagnetism have in the main been studied and presented in isolation from each other. This text draws together these lines of inquiry into an integrated framework to highlight the interrelationships and thus to provide a more comprehensive understanding of the geomagnetic field.

This book addresses and reviews many of the still little understood questions related to the processes underlying planetary magnetic fields and their interaction with the solar wind. With focus on research carried out within the German Priority Program ”PlanetMag”, it also provides an overview of the most recent research in the field. Magnetic fields play an important role in making a planet habitable by protecting the environment from the solar wind. Without the geomagnetic field, for example, life on Earth as we know it would not be possible. And results from recent space missions to Mars and Venus strongly indicate that planetary magnetic fields play a vital role in preventing atmospheric erosion by the solar wind. However, very little is known about the underlying interaction between the solar wind and a planet’s magnetic field. The book takes a synergistic interdisciplinary approach that combines newly developed tools for data acquisition and analysis, computer simulations of planetary interiors and dynamos, models of solar wind interaction, measurement of ancient terrestrial rocks and meteorites, and laboratory investigations.

The mystery of how migrating animals find their way over unfamiliar terrain has intrigued people for centuries, and has been the focus of productive research in the biological sci ences for several decades. Whether or not the earth's magnetic field had anything to do with their navigational abilities has sufaced and been dismissed several times, beginning at least in the mid to late 1800s. This topic generally remained out of the mainstream of scientific research for two reasons: (1) The apparent irreproducibility of many of the be havioral experiments which were supposed to demonstrate the existence of the magnetic sense; and (2) Perceived theoretical difficulties which were encountered when biophysi cists tried to understand how such a sensory system might operate. However, during the mid to late 1960s as the science of ethology (animal behavior) grew, it became clear from studies on bees and birds that the geomagnetic field is used under a variety of conditions. As more and more organisms were found to have similar abilities, the problem shifted back to the question as to the basis of this perception. Of the various schemes for trans ducing the geomagnetic field to the nervous system which have been proposed, the hy pothesis of magnetite-based magnetoreception discussed at length in this volume has per haps the best potential for explaining a wide range of these effects, even though this link is as yet clear only in the case of magnetotactic bacteria.

The dynamics of physical, chemical, biological, or fluid systems generally must be described by nonlinear models, whose detailed mathematical solutions are not obtainable. To understand some aspects of such dynamics, various complementary methods and viewpoints are of crucial importance. In this book the perspectives generated by analytical, topological and computational methods, and interplays between them, are developed in a variety of contexts. This book is a comprehensive introduction to this field, suited to a broad readership, and reflecting a wide range of applications. Some of the concepts considered are: topological equivalence; embeddings; dimensions and fractals; Poincaré maps and map-dynamics; empirical computational sciences vis-á-vis mathematics; Ulam's synergetics; Turing's instability and dissipative structures; chaos; dynamic entropies; Lorenz and Rossler models; predator-prey and replicator models; FPU and KAM phenomena; solitons and nonsolitons; coupled maps and pattern dynamics; cellular automata.

The main magnetic field of the Earth is a complex phenomenon. To understand its origins in the fluid of the Earth's core, and how it changes in time requires a variety of mathematical and physical tools. This book presents the foundations of geomagnetism, in detail and developed from first principles. The book is based on George Backus' courses for graduate students at the University of California, San Diego. The material is mathematically rigorous, but is logically developed and has consistent notation, making it accessible to a broad range of readers. The book starts with an overview of the phenomena of interest in geomagnetism, and then goes on to deal with the phenomena in detail, building the necessary techniques in a thorough and consistent manner. Students and researchers will find this book to be an invaluable resource in the appreciation of the mathematical and physical foundations of geomagnetism.