Relativity and Engineering

The main feature of this book is the emphasis on "practice". This approach, unusual in the relativistic literature, may be clarified by quoting some problems discussed in the text: - the analysis of rocket acceleration to relativistic velocities - the influence of gravitational fields on the accuracy of time measurements - the operation of optical rotation sensors - the evaluation of the Doppler spectrum produced by the linear (or ro- tional) motion of an antenna or scatterer - the use of the Cerenkov effect in the design of millimeter-wave power generators - the influence of the motion of a plasma on the transmission of electrom- netic waves through this medium. A correct solution of these (and analogous) problems requires the use of re- lativistic principles. This remark remains valid even at low velocities, since first-order terms in (v/c) often playa fundamental role in the equations. The "applicational" approach used in the text should be acceptable to space engineers, nuclear engineers, electrical engineers, and more generally, ap- plied physicists. Electrical engineers, in particular, are concerned with re- lativity by way of the electrodynamics of moving bodies. This discipline is of decisive importance for power engineers, who are confronted with problems such as - the justification of a forcing function (-D~/Dt) in the circuit equation of a moving loop - a correct formulation of Maxwell's equations in rotating coordinate systems - the resolution of "sliding contact" paradoxes - a theoretically satisfying analysis of magnetic levitation systems.

1. Kinematics in Inertial Axes.- 1.1 The “Aether” in the Nineteenth Century.- 1.2 Some Experimental Evidence.- 1.3 Einstein’s Relativity Postulates.- 1.4 Time and Length Standards. Synchronization.- 1.5 The “Simple” Lorentz Transformation.- 1.6 More General Lorentz Transformations.- 1.7 Time Dilatation and Proper Time.- 1.8 Length Measurements.- 1.9 Volume and Surface Elements.- 1.10 Visual Perception of Objects in Motion.- 1.11 Transformation of Velocities and Accelerations.- 1.12 Four-Vectors.- 1.13 Kinematics in Four Dimensions.- Problems.- 2. Dynamics in Inertial Axes.- 2.1 Equation of Motion of a Point Mass.- 2.2 Mass and Energy.- 2.3 A Few Simple Trajectories.- 2.4 Transformation Equations for Force, Energy, and Momentum.- 2.5 Four-Dimensional Dynamics.- 2.6 Systems of Points.- 2.7 Elastic Collisions.- 2.8 Motion of a Point with Variable Rest Mass.- 2.9 Rocket Acceleration.- 2.10 Inelastic Collisions.- 2.11 Incoherent Matter.- 2.12 The Kinetic Energy-Momentum Tensor.- 2.13 The Total Energy-Momentum Tensor.- Problems.- 3. Vacuum Electrodynamics in Inertial Axes.- 3.1 Transformation Formulas for the Sources.- 3.2 Transformation Equations for the Fields.- 3.3 Force on a Charged Particle.- 3.4 Four-Currents.- 3.5 The Electromagnetic Tensors.- 3.6 Potentials.- 3.7 Transformation of a Plane Wave: The Doppler Effect.- 3.8 The Liénard-Wiechert Fields.- 3.9 Fields of a Charge in Uniform Motion.- 3.10 Fields of a Static Dipole in Uniform Motion.- 3.11 Radiation from an Antenna in Uniform Motion.- 3.12 Radiation from a Moving Oscillation Dipole.- 3.13 Doppler Spectrum from a Moving Source.- Problems.- 4. Fields in Media in Uniform Translation.- 4.1 Polarization Densities.- 4.2 Constitutive Equations.- 4.3 Some Useful Forms of Maxwell’s Equations.- 4.4 Point Charge Moving Uniformly in a Dielectric Medium.- 4.5 The Cerenkov Effect.- 4.6 Waves in a Moving Dielectric. The Fresnel Dragging Coefficient.- 4.7 Green’s Dyadic for a Moving Dielectric.- 4.8 Electric Dipole Radiating in a Moving Dielectric.- Problems.- 5. Boundary-Value Problems for Media in Uniform Translation.- 5.1 Boundary Conditions.- 5.2 Dielectric Slab Moving in Time-Independent Fields.- 5.3 The Wilsons’ Experiment.- 5.4 Sliding Contacts. A Simple Problem.- 5.5 Material Bodies Moving at Low Velocities.- 5.6 Conductors Moving in a Pre-Existing Static Magnetic Field.- 5.7 Circuit Equations.- 5.8 Motional E.M.F..- 5.9 Normal Incidence of a Time-Harmonic Plane Wave on a Moving Mirror.- 5.10 Arbitrary Time-Dependence of the Incident Plane Wave.- 5.11 Oblique Incidence of a Time-Harmonic Plane Wave on a Moving Mirror.- 5.12 A Time-Harmonic Plane Wave Incident on a Dielectric Medium.- 5.13 Reflection of a Plane Wave on a Moving Medium of Finite Conductivity.- 5.14 Revisiting the Boundary Conditions at a Moving Interface.- 5.15 Scattering by a Cylinder Moving Longitudinally.- 5.16 Scattering by a Cylinder Moving Transversely.- 5.17 Three-Dimensional Scattering by Moving Bodies.- 5.18 The Quasistationary Method.- Problems.- 6. Electromagnetic Forces and Energy.- 6.1 Surface and Volume Forces in Vacuum.- 6.2 Maxwell’s Stress Tensor.- 6.3 A Few Simple Force Calculations.- 6.4 Radiation Pressure on a Moving Mirror.- 6.5 Radiation Force on a Dielectric Cylinder.- 6.6 Static Electric Force on a Dielectric Body.- 6.7 Magnetic Levitation.- 6.8 Levitation on a Line Current.- 6.9 Electromagnetic Energy in an Inertial System.- 6.10 Four-Dimensional Formulation in Vacuum.- 6.11 The Electromagnetic Energy-Momentum Tensor in Material Media.- Problems.- 7. Accelerated Systems of Reference.- 7.1 Coordinate Transformations.- 7.2 The Metric Tensor.- 7.3 Examples of Transformations.- 7.4 Coordinates and Measurements.- 7.5 Time and Length.- 7.6 Four-Vectors and Tensors.- 7.7 Three-Vectors.- 7.8 Velocities and Volume Densities.- 7.9 Covariant Derivative.- Problems.- 8. Gravitation.- 8.1 Inertial and Gravitational Masses.- 8.2 The Principle of Equivalence.- 8.3 Curvature.- 8.4 Einstein’s Equations.- 8.5 The Small-Field Approximation.- 8.6 Gravitational Frequency Shift.- 8.7 Time Measurement Problems.- 8.8 Some Important Solutions of Einstein’s Equations.- 8.9 Point Dynamics.- 8.10 Motion in the Schwarzschild Metric.- 8.11 Motion of a Photon in the Schwarzschild Metric.- 8.12 Strongly Concentrated Masses.- 8.13 Static Cosmological Metrics.- 8.14 Nonstatic Cosmological Metrics.- 8.15 Recent Cosmological Observations.- Problems.- 9. Maxwell’s Equations in a Gravitational Field.- 9.1 Field Tensors and Maxwell’s Equations.- 9.2 Maxwell’s Equations in Rotating Coordinates.- 9.3 Transformation Equations for Fields and Sources.- 9.4 Constitutive Equations in Vacuum.- 9.5 Constitutive Equations in a Time-Orthogonal Metric.- 9.6 Constitutive Equations in Material Media.- 9.7 The Co-Moving Frame Assumption.- 9.8 Boundary Conditions.- Problems.- 10. Electromagnetism of Accelerated Bodies.- 10.1 Conducting Body of Revolution Rotating in a Static Magnetic Field.- 10.2 Conducting Sphere Rotating in a Uniform Magnetic Field.- 10.3 Motional E.M.F.- 10.4 Generators with Contact Electrodes.- 10.5 Dielectric Body of Revolution Rotating in a Static Field.- 10.6 Rotating Permanent Magnets.- 10.7 Scattering by a Rotating Circular Dielectric Cylinder.- 10.8 Scattering by a Rotating Circular Conducting Cylinder.- 10.9 Scattering by a Rotating Dielectric Body of Revolution.- 10.10 Scattering by a Rotating Sphere.- 10.11 Reflection from a Mirror in Arbitrary Linear Motion.- 10.12 Reflection from an Oscillating Mirror, at Normal Incidence.- 10.13 Reflection from an Oscillating Mirror, at Oblique Incidence.- 10.14 Scattering by Other Moving Surfaces.- Problems.- 11. Field Problems in a Gravitational Field.- 11.1 Fields Associated with Rotating Charges.- 11.2 Schiff’s Paradox.- 11.3 Kennard’s Experiment.- 11.4 Optical Rotation Sensors.- 11.5 Scattering by a Rotating Body of Arbitrary Shape.- 11.6 Transformation of an Incident Wave to Rotating Coordinates.- 11.7 Scattered Field in Rotating Coordinates.- 11.8 Two Examples.- 11.9 Low Frequency Scattering by Rotating Cylinders.- 11.10 Quasistationary and Relativistic Fields.- 11.11 Axes in Hyperbolic Motion.- 11.12 The Induction Law.- 11.13 Maxwell’s Equations in a Schwarzschild Metric.- 11.14 Light Deflection in a Gravitational Field.- Problems.- Appendix A. Complements of Kinematics and Dynamics.- A.1 Transformation Matrix for the “Parallel” Transformation.- A.2 Transformation with Rotation.- A.3 Transformation of Velocities.- A.4 Relationship Between Force and Acceleration.- A.5 Equations of Motion in Cylindrical Coordinates (r,?,z).- A.6 Equations of Motion in Spherical Coordinates (R,?,?).- Appendix B. Dyadics.- B.1 The Dyadic Notation.- B.2 Operators on Dyadics.- B.3 Green’s Dyadic.- Appendix C. Basis Vectors.- Appendix D. Moving Open Circuits.- List of Symbols.- Some Useful Numerical Constants.- References.