Conversations on Electric And Magnetic Fields in the Cosmos

by Parker, Eugene N.

• ISBN13: 9780691128412
• ISBN10: 0691128413
• Format: Paperback
• Copyright: 2007-01-29
• Publisher: Princeton Univ Pr

Summary

Today's standard textbooks treat the theoretical structure of electric and magnetic fields, but their emphasis is on electromagnetic radiation and static-electric and magnetic fields. In this book, Eugene Parker provides advanced graduate students and researchers with a much-needed complement to existing texts, one that discusses the dynamic electromagnetism of the cosmos--that is, the vast magnetic fields that are carried bodily in the swirling ionized gases of stars and galaxies and throughout intergalactic space. Parker is arguably the world's leading authority on solar wind and the effects of magnetic fields in the heliosphere, and his originality of thought and distinctive approach to physics are very much in evidence here. Seeking to enrich discussions in standard texts and correct misconceptions about the dynamics of these large-scale fields, Parker engages readers in a series of "conversations" that are at times anecdotal and even entertaining without ever sacrificing theoretical rigor. The dynamics he describes represents the Maxwell stresses of the magnetic field working against the pressure and inertia of the bulk motion of ionized gases, characterized in terms of the magnetic field and gas velocity. Parker shows how this dynamic interaction cannot be fully expressed in terms of the electric current and electric field. Conversations on Electric and Magnetic Fields in the Cosmosgoes back to basics to explain why classical hydrodynamics and magnetohydrodynamics are inescapable, even in the deepest reaches of space.

Author Biography

Eugene N. Parker is S. Chandrasekhar Distinguished Service Professor Emeritus of Physics and Astronomy at the University of Chicago

Table of Contents

List of Illustrations	p. xi
Acknowledgments	p. xiii
Introduction	p. 1
General Remarks	p. 1
Electromagnetic Field Equations	p. 3
Electrical Neutrality	p. 7
Electric Charge and Magnetic Field Dominance	p. 12
Electric Fields	p. 15
Basic Considerations	p. 15
Definition of Charge and Field	p. 16
Concept of Electric Field	p. 17
Physical Reality of Electric Field	p. 20
Electric Field Pressure	p. 22
Magnetic Fields	p. 25
Basic Considerations	p. 25
Experimental Connection	p. 26
Differential Form of Ampere's Law	p. 27
Energy and Stress	p. 29
Detecting a Magnetic Field	p. 32
Field Lines	p. 37
Basic Considerations	p. 37
The Optical Analogy	p. 39
Maxwell's Equations	p. 43
Maxwell and Poynting	p. 48
Poynting's Momentum and Energy Theorems	p. 48
Applications	p. 52
Electric and Magnetic Fields in Matter	p. 52
SI Units	p. 55
Systems of Units	p. 59
Chaucer Units	p. 63
Moving Reference Frames	p. 65
Lorentz Transformations	p. 65
Electric Fields in the Laboratory	p. 66
Occam's Razor and the Tree in the Forest	p. 67
Electric Field in a Moving Plasma	p. 68
Net Charge in a Swirling Plasma	p. 71
Hydrodynamics	p. 74
Basic Considerations	p. 74
Derivation of the HD Equations	p. 76
The Pressure Tensor	p. 79
Pressure Variation in Uniform Dilatations	p. 82
Shear Flow	p. 85
Effects of Collisions	p. 86
Off-diagonal Terms and Viscosity	p. 89
Summary	p. 91
Magnetohydrodynamics	p. 92
Basic Considerations	p. 92
Diffusion and Dissipation	p. 96
Application of Magnetic Diffusion	p. 98
Discussion	p. 101
Partially Ionized Gases	p. 102
An Electric Current to Satisfy Ampere	p. 108
Particle Motion Along B	p. 114
Time-varying Magnetic Field	p. 119
Comments	p. 121
Singular Properties of the Maxwell Stress Tensor	p. 123
Magnetic Equilibrium	p. 123
Calculation of the Equilibrium Field	p. 128
Equilibrium in Stretched Field	p. 129
Resolving the Contradiction	p. 132
Formation of TDs	p. 133
Rapid Reconnection at an Incipient TD	p. 137
Quasi-steady Dissipation at a TD	p. 142
Comments	p. 147
Summary	p. 147
Electric Circuit Analogy	p. 148
A Simple Example of an Electric Circuit	p. 149
Popular Electric and Magnetic Fields	p. 154
Electrostatically Driven Expansion of the Universe	p. 157
Relaxation of Electric Charge Inhomogeneity	p. 159
Imposition of a Large-scale Electric Field	p. 162
Electric Charge Density in an Electric Field	p. 165
The Transverse Invariant wn2B	p. 167
Blocking the Flow of Electric Current	p. 169
References	p. 173
Index	p. 179
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