Waves and Rays in Elastic Continua


Book Description

This is the second edition of the textbook that was first published by Elsevier Science. Professor Slawinski has the copyright to the textbook and the second edition is significantly extended. The present book emphasizes the interdependence of mathematical formulation and physical meaning in the description of seismic phenomena. Herein, we use aspects of continuum mechanics, wave theory and ray theory to explain phenomena resulting from the propagation of seismic waves. The book is divided into three main sections: elastic continua, waves and rays and variational formulation of rays. There is also a fourth part, which consists of appendices. In Part 1, we use continuum mechanics to describe the material through which seismic waves propagate, and to formulate a system of equations to study the behaviour of such a material. In Part 2, we use these equations to identify the types of body waves propagating in elastic continua as well as to express their velocities and displacements in terms of the properties of these continua. To solve the equations of motion in anisotropic inhomogeneous continua, we use the high-frequency approximation and, hence, establish the concept of a ray. In Part 3, we show that, in elastic continua, a ray is tantamount to a trajectory along which a seismic signal propagates in accordance with the variational principle of stationary traveltime. Consequently, many seismic problems in elastic continua can be conveniently formulated and solved using the calculus of variations. In Part 4, we describe two mathematical concepts that are used in the book; namely, homogeneity of a function and Legendre's transformation. This section also contains a list of symbols.




Waves And Rays In Elastic Continua (3rd Edition)


Book Description

The present book — which is the third, significantly revised edition of the textbook originally published by Elsevier Science — emphasizes the interdependence of mathematical formulation and physical meaning in the description of seismic phenomena. Herein, we use aspects of continuum mechanics, wave theory and ray theory to explain phenomena resulting from the propagation of seismic waves.The book is divided into three main sections: Elastic Continua, Waves and Rays and Variational Formulation of Rays. There is also a fourth part, which consists of appendices.In Elastic Continua, we use continuum mechanics to describe the material through which seismic waves propagate, and to formulate a system of equations to study the behaviour of such a material. In Waves and Rays, we use these equations to identify the types of body waves propagating in elastic continua as well as to express their velocities and displacements in terms of the properties of these continua. To solve the equations of motion in anisotropic inhomogeneous continua, we invoke the concept of a ray. In Variational Formulation of Rays, we show that, in elastic continua, a ray is tantamount to a trajectory along which a seismic signal propagates in accordance with the variational principle of stationary traveltime. Consequently, many seismic problems in elastic continua can be conveniently formulated and solved using the calculus of variations. In the Appendices, we describe two mathematical concepts that are used in the book; namely, homogeneity of a function and Legendre's transformation. This section also contains a list of symbols.




Seismic Waves and Rays in Elastic Media


Book Description

This book seeks to explore seismic phenomena in elastic media and emphasizes the interdependence of mathematical formulation and physical meaning. The purpose of this title - which is intended for senior undergraduate and graduate students as well as scientists interested in quantitative seismology - is to use aspects of continuum mechanics, wave theory and ray theory to describe phenomena resulting from the propagation of waves.The book is divided into three parts: Elastic continua, Waves and rays, and Variational formulation of rays. In Part I, continuum mechanics are used to describe the material through which seismic waves propagate, and to formulate a system of equations to study the behaviour of such material. In Part II, these equations are used to identify the types of body waves propagating in elastic continua as well as to express their velocities and displacements in terms of the properties of these continua. To solve the equations of motion in anisotropic inhomogeneous continua, the high-frequency approximation is used and establishes the concept of a ray. In Part III, it is shown that in elastic continua a ray is tantamount to a trajectory along which a seismic signal propagates in accordance with the variational principle of stationary travel time.




Waves And Rays In Seismology: Answers To Unasked Questions (Second Edition)


Book Description

'In summary, Professor Slawinski has written an engaging volume covering an unfamiliar topic in a highly accessible fashion. Non-specialists will gain a significant appreciation of the unique complexities associated with seismology.'Contemporary PhysicsThe author dedicates this book to readers who are concerned with finding out the status of concepts, statements and hypotheses, and with clarifying and rearranging them in a logical order. It is thus not intended to teach tools and techniques of the trade, but to discuss the foundations on which seismology — and in a larger sense, the theory of wave propagation in solids — is built. A key question is: why and to what degree can a theory developed for an elastic continuum be used to investigate the propagation of waves in the Earth, which is neither a continuum nor fully elastic. But the scrutiny of the foundations goes much deeper: material symmetry, effective tensors, equivalent media; the influence (or, rather, the lack thereof) of gravitational and thermal effects and the rotation of the Earth, are discussed ab initio. The variational principles of Fermat and Hamilton and their consequences for the propagation of elastic waves, causality, Noether's theorem and its consequences on conservation of energy and conservation of linear momentum are but a few topics that are investigated in the process to establish seismology as a science and to investigate its relation to subjects like realism and empiricism in natural sciences, to the nature of explanations and predictions, and to experimental verification and refutation.In the second edition, new sections, figures, examples, exercises and remarks are added. Most importantly, however, four new appendices of about one-hundred pages are included, which can serve as a self-contained continuum-mechanics course on finite elasticity. Also, they broaden the scope of elasticity theory commonly considered in seismology.




Waves And Rays In Elastic Continua (Fourth Edition)


Book Description

Seismology, as a branch of mathematical physics, is an active subject of both research and development. Its reliance on computational and technological advances continuously motivates the developments of its underlying theory. The fourth edition of Waves and Rays in Elastic Continua responds to these needs.The book is both a research reference and a textbook. Its careful and explanatory style, which includes numerous exercises with detailed solutions, makes it an excellent textbook for the senior undergraduate and graduate courses, as well as for an independent study. Used in its entirety, the book could serve as a sole textbook for a year-long course in quantitative seismology. Its parts, however, are designed to be used independently for shorter courses with different emphases. The book is not limited to quantitive seismology; it can serve as a textbook for courses in mathematical physics or applied mathematics.




Nonlinear Periodic Waves and Their Modulations


Book Description

Although the mathematical theory of nonlinear waves and solitons has made great progress, its applications to concrete physical problems are rather poor, especially when compared with the classical theory of linear dispersive waves and nonlinear fluid motion. The Whitham method, which describes the combining action of the dispersive and nonlinear effects as modulations of periodic waves, is not widely used by applied mathematicians and physicists, though it provides a direct and natural way to treat various problems in nonlinear wave theory. Therefore it is topical to describe recent developments of the Whitham theory in a clear and simple form suitable for applications in various branches of physics.This book develops the techniques of the theory of nonlinear periodic waves at elementary level and in great pedagogical detail. It provides an introduction to a Whitham's theory of modulation in a form suitable for applications. The exposition is based on a thorough analysis of representative examples taken from fluid mechanics, nonlinear optics and plasma physics rather than on the formulation and study of a mathematical theory. Much attention is paid to physical motivations of the mathematical methods developed in the book. The main applications considered include the theory of collisionless shock waves in dispersive systems and the nonlinear theory of soliton formation in modulationally unstable systems. Exercises are provided to amplify the discussion of important topics such as singular perturbation theory, Riemann invariants, the finite gap integration method, and Whitham equations and their solutions.




Seismic Waves and Rays in Elastic Media


Book Description

This book seeks to explore seismic phenomena in elastic media and emphasizes the interdependence of mathematical formulation and physical meaning. The purpose of this title - which is intended for senior undergraduate and graduate students as well as scientists interested in quantitative seismology - is to use aspects of continuum mechanics, wave theory and ray theory to describe phenomena resulting from the propagation of waves. The book is divided into three parts: Elastic continua, Waves and rays, and Variational formulation of rays. In Part I, continuum mechanics are used to describe the material through which seismic waves propagate, and to formulate a system of equations to study the behaviour of such material. In Part II, these equations are used to identify the types of body waves propagating in elastic continua as well as to express their velocities and displacements in terms of the properties of these continua. To solve the equations of motion in anisotropic inhomogeneous continua, the high-frequency approximation is used and establishes the concept of a ray. In Part III, it is shown that in elastic continua a ray is tantamount to a trajectory along which a seismic signal propagates in accordance with the variational principle of stationary travel time.




Methods of Wave Theory in Dispersive Media


Book Description

Ch. 1. Linear harmonic waves in dispersive systems. Initial-value problem and problem with an external source. 1. Harmonic waves in dispersive systems. 2. Initial-value problem. Eigenmode method. 3. Characteristic function of the state vector. Dispersion operator. 4. Laplace transform method -- ch. 2. A case study of linear waves in dispersive media. 5. Transverse electromagnetic waves in an isotropic dielectric. 6. Longitudinal electrostatic waves in a cold isotropic plasma. Collisional dissipation of plasma waves. 7. Transverse electromagnetic waves in a cold isotropic plasma. Dissipation of transverse waves in a plasma. 8. Electromagnetic waves in metals. 9. Electromagnetic waves in a waveguide with an isotropic dielectric. 10. Longitudinal waves in a hot isotropic plasma. Electron diffusion in a plasma. 11. Longitudinal waves in an isotropic degenerate plasma. Waves in a quantum plasma. 12. Ion acoustic waves in a nonisothermal plasma. Ambipolar diffusion. 13. Electromagnetic waves in a waveguide with an anisotropic plasma in a strong external magnetic field. 14. Electromagnetic waves propagating in a magnetized electron plasma along a magnetic field. 15. Electrostatic waves propagating in a magnetized electron plasma at an angle to a magnetic field. 16. Magnetohydrodynamic waves in a conducting fluid. 17. Acoustic waves in crystals. 18. Longitudinal electrostatic waves in a one-dimensional electron beam. 19. Beam instability in a plasma. 20. Instability of a current-carrying plasma -- ch. 3. Linear waves in coupled media. Slow amplitude method. 21. Coupled oscillator representation and slow amplitude method. 22. Beam-plasma system in the coupled oscillator representation. 23. Basic equations of microwave electronics. 24. Resonant Buneman instability in a current-carrying plasma in the coupled oscillator representation. 25. Dispersion function and wave absorption in dissipative systems. 26. Some effects in the interaction between waves in coupled systems. 27. Waves and their interaction in periodic structures -- ch. 4. Nonharmonic waves in dispersive media. 28. General solution to the initial-value problem. 29. Quasi-harmonic approximation. Group velocity. 30. Pulse spreading in equilibrium dispersive media. 31. Stationary-phase method. 32. Some problems for wave equations with a source -- ch. 5. Nonharmonic waves in nonequilibrium media. 33. Pulse propagation in nonequilibrium media. 34. Stationary-phase method for complex frequencies. 35. Quasi-harmonic approximation in the theory of interaction of electron beams with slowing-down media -- ch. 6. Theory of instabilities. 36. Convective and absolute instabilities. First criterion for the type of instability. 37. Saddle-point method. Second criterion for the type of instability. 38. Third Criterion for the type of instability. 39. Type of beam instability in the interaction with a slowed wave of zero group velocity in a medium. 40. Calculation of the Green's functions of unstable systems -- ch. 7. Hamiltonian method in the theory of electromagnetic radiation in dispersive media. 41. Equations for the excitation of transverse electromagnetic field oscillators. 42. Dipole radiation. 43. Radiation from a moving dipole - undulator radiation. 44. Cyclotron radiation. 45. Cherenkov effect. Anomalous and normal doppler effects. 46. Application of the Hamiltonian method to the problem of the excitation of longitudinal waves




Waves And Rays In Elastic Continua


Book Description

The present book — which is the second, and significantly extended, edition of the textbook originally published by Elsevier Science — emphasizes the interdependence of mathematical formulation and physical meaning in the description of seismic phenomena. Herein, we use aspects of continuum mechanics, wave theory and ray theory to explain phenomena resulting from the propagation of seismic waves.The book is divided into three main sections: Elastic Continua, Waves and Rays and Variational Formulation of Rays. There is also a fourth part, which consists of appendices.In Elastic Continua, we use continuum mechanics to describe the material through which seismic waves propagate, and to formulate a system of equations to study the behaviour of such a material. In Waves and Rays, we use these equations to identify the types of body waves propagating in elastic continua as well as to express their velocities and displacements in terms of the properties of these continua. To solve the equations of motion in anisotropic inhomogeneous continua, we invoke the concept of a ray. In Variational Formulation of Rays, we show that, in elastic continua, a ray is tantamount to a trajectory along which a seismic signal propagates in accordance with the variational principle of stationary traveltime. Consequently, many seismic problems in elastic continua can be conveniently formulated and solved using the calculus of variations. In the Appendices, we describe two mathematical concepts that are used in the book; namely, homogeneity of a function and Legendre's transformation. This section also contains a list of symbols.