Physics of Dielectrics for the Engineer

Physics of Dielectrics for the Engineer is a systematic attempt to clarify and correlate advanced concepts underlying the physics of dielectrics. It reviews the basics of electrostatics, the different models for the polarizability of atoms and molecules, and the macroscopic permittivity. It also discusses the behavior of matter in an alternating field in relation to complex permittivity, the interactions between field and matter, dissipative effects under high electric fields, the wide-gap semiconductor model, the types of charge carriers, and the main disruptive processes. Organized into three parts encompassing 12 chapters, this volume begins with an overview of the physical concepts involved in the behavior of insulating materials subjected to high electric fields. It then explores the potential of a group of charges, and dipoles induced in an applied field. The book explains statistical theories of dipole orientation in an applied field and theories relating molecular and macroscopic quantities. The propagation of an electromagnetic wave, dipole relaxation of defects in crystal lattices, and space-charge polarization and relaxation are also discussed. The book explains the uni-dimensional polar lattice, intrinsic and impurity conduction in wide-gap semiconductors, thermal runaway, and collision breakdown. Many problems with corresponding solutions are included to assist the reader. This book will benefit electrical engineers, as well as electrical engineering students, scientists, and technicians.

Preface List of Symbols Part 1. Matter in a Constant Electric Field I. Introduction - Condensed review of electrostatics II. The potential of a group of charges II.1. Multipolar expansions II.2. Multipolar expansion of a single point charge II.3. Multipolar expansion of a real dipole III. Dipoles induced in an applied field III.1. Quantum mechanical approach of electronic polarizability III.2. Elementary models for spherical atoms and molecules III.3. Elementary models for non-spherical atoms and molecules III.4. Harmonic oscillator model for the ionic polarizability IV. Statistical theories of dipole orientation in an applied field IV.1. Case of free point dipoles (Langevin's theory) IV.2. Case of point dipoles in crystal lattices IV.3. Case of polarizable dipoles with Δα > O V. Theories relating the molecular quantities to the macroscopic ones V.1. Dilute phases V.2. Condensed non-polar phases. Lorentz theory V.3. Condensed phases. Onsager theory V.4. The Kerr electro-optic effect Part 2. Matter in an Alternating Field VI. The complex permittivity VI.1. Definition of ε and σ. Propagation of an electromagnetic wave VI.2. The various types of charges and charge groups, and the corresponding interactions VI.3. The response of a linear material to a variable field VI.4. Case of an a.c. field. Kramers-Kronig relations VII. Relaxations VII.1. Introductory remarks VII.2. Mechanical analogue of a relaxation VII.3. Advanced formalism. Definitions and theorems VII.4. Application to dipole relaxation - Debye relation VII.5. The ε”(ε1) representation (Argand diagram) VII.6. Corrections to the Debye theory VII.7. Interfacial relaxation. Maxwell-Wagner effect