The Earth's magnetic field has existed for hundreds of millions of years, far longer than life has existed on Earth, and affects our lives in many ways. We can use it to orient buildings and navigate across unmarked territory. Moreover, it protects us from harmful radiation from space.
Intended as an introductory guide for non-specialist readers, this book describes the historical importance of the Earth's magnetic field and its role in protecting the planet from harmful high-energy radiation from the Sun. With explanations of underlying physics of processes and references to original scientific works, the reader can explore the Earth's magnetic field and the various ways in which geomagnetics are used and measured, including the analysis of modern satellite-based investigations and the effects of solar activity on the geomagnetic field.
Author(s): William Lowrie
Edition: 1
Publisher: Oxford University Press
Year: 2023
Language: English
Pages: 176
City: New York
Tags: Earth; Earth Magnetic Field; Geomagnetism; Geomagnetic Field; Magnetism; Terrestrial Magnetism; Magnetic Field
cover
titlepage
copyright
Foreword
Contents
List of Illustrations
1 What is Magnetism?
1.1 The Discovery of Magnetism
1.2 The Earth as a Magnet
1.3 The Origin of Magnetic Fields
1.4 Electrical Currents and Magnetic Fields
1.5 Magnetism at the Atomic Level: The Bohr Model of the Atom
1.6 Spectral Analysis and the Zeeman Effect
1.7 Electromagnetism
1.8 Particle Radiation
2 How the Geomagnetic Field is Measured
2.1 Measurement of Magnetic Field Direction
2.2 Measurement of Magnetic Field Intensity
2.3 Vector Magnetometers
2.4 Scalar Magnetometers
2.5 Magnetic Gradiometers
2.6 Terrestrial Magnetic Surveying
2.7 Magnetic Observatories
2.8 Satellite Mapping of the Global Magnetic Field
2.9 The Geomagnetic Field at the Earth's Surface
3 Sources of the Earth's Magnetic Field
3.1 The Earth's Internal Structure
3.2 Pressure and Temperature in the Earth
3.3 Dipole and Multipole Fields
3.4 Internal and External Sources of the Magnetic Field
3.5 Spherical Harmonic Analysis of the Internal Field
3.6 The International Geomagnetic Reference Field
3.7 Spatial Power Spectrum of the Internal Field
3.8 The Lithospheric Magnetic Field
4 The Geomagnetic Dynamo
4.1 The Concept of a Self-sustaining Geodynamo
4.2 Heat Transport in the Core
4.3 The Coriolis Force Due to the Earth's Rotation
4.4 Magnetohydrodynamics and the Frozen-Flux Concept
4.5 The Dynamo Model for the Origin of the Internal Magnetic Field
4.6 The Magnetic Influence of the Inner Core
4.7 The Magnetic Field at the Core–Mantle Boundary
4.8 Archeomagnetic Secular Variation of Paleointensity
4.9 The Geomagnetic Field in the Early Earth
5 The Magnetism of the Earth's Crust
5.1 Physical Properties of the Crust and Mantle
5.2 Crustal Rock Types
5.3 Types of Magnetism in Minerals
5.4 Antiferromagnetic and Ferrimagnetic Minerals
5.5 Induced and Remanent Magnetizations
5.6 The Thickness of the Magnetized Crustal Layer
5.7 How a Magnetic Anomaly Originates
5.8 Continental Magnetic Anomalies
5.9 The Magnetization of the Oceanic Crust
5.10 The Age of the Ocean Floor
6 The Ancient Geomagnetic Field
6.1 The Natural Remanent Magnetizations of Rocks
6.2 The Geocentric Axial Dipole Hypothesis
6.3 Methods of Paleomagnetism
6.4 Apparent Polar Wander and Continental Reconstructions
6.5 Geomagnetic Polarity Reversals
6.6 Magnetic Polarity Stratigraphy
6.7 Geomagnetic Polarity in the Early Mesozoic and Paleozoic
6.8 The Geomagnetic Field in the Precambrian
7 The Effects of Solar Activity on the Geomagnetic Field
7.1 The Internal Structure of the Sun
7.2 Energy Transfer in the Sun
7.3 Sunspots and the Solar Cycle
7.4 The Sun's Magnetic Field
7.5 The Solar Wind
7.6 The Interplanetary Magnetic Field
7.7 Coronal Mass Ejections and Solar Flares
8 The Magnetosphere and Ionosphere
8.1 The Magnetosphere
8.2 The Van Allen Radiation Belts
8.3 The Ionosphere
8.4 Electromagnetic Induction in the Crust and Mantle
8.5 Magnetic Storms and Substorms
8.6 Space Weather
References
Index
