Dielectric Materials and Electrostatics

Oliver Gallot-Lavallée, University Joseph Fourier, Grenoble, France

• Foreword ixChapter 1 Mathematical Examination of Dielectrics 11.1.Introduction to dielectrics 11.1.1.Polarization 31.1.2.Ionization 41.1.3.Polarized dielectrics 51.1.4.Electrical induction 101.1.5.Move from one dielectric to another 111.1.6.Move from a dielectric to a conductor 121.1.7.Energy contained in a dielectric 131.2.Perfect dielectrics 151.2.1.Refraction of force-and induction-lines 161.2.2. Field in the vicinity of a charged conductor. 191.2.3 Electrostatic pressure 201.2.4.Corresponding elements 211.2.5.Equilibrium in a system of conductors 221.2.6.Capacities and influence coefficients 231.2.7.Calculation of the interstitial field 251.2.8.Depolarizing field 271.3.Forces exerted on polarized dielectrics 341.3.1 Forces exerted on a rigidly-polarized solid dielectric 341.3.2. Forces exerted on a solid perfect dielectric 371.3.3 Forces exerted on a liquid dielectric 411.3.4.Electrostriction 441.4 Dielectric losses 451.5.Residual charges 501.6.Electrets 511.7.Characteristics of an insulator 521.8.Pyro and piezo-electricity 541.8.1.Pyroelectricity 551.8.2.Piezoelectricity 561.9.Currents in extended conductors 631.9.1.Current density 631.9.2 Expression of Ohm’s law in an extended conductor 651.9.3.Conservation of current density 671.9.4 Distribution of current in an extended medium 671.9.5.Power dissipated by the Joule effect 701.9.6.Resistance of the conductive medium 701.9.7 Deviation of the electrical current when crossing the surface separating two conductors 77Chapter 2. Physical Examination of Dielectrics 812.1.Gaseous dielectrics 812.1.1.Reminder of the properties of gases 812.1.2.Ionization 892.1.3 Examination of the conditions of initiation of self-sustaining discharge 952.1.4.Corona discharge effect 1102.1.5.Use of gases as insulators 1342.2.Liquid and solid dielectrics 1382.2.1.Conductivity 1382.2.2.Physics of polarization 1412.2.3.Dielectric losses 1552.2.4.Breakdown of solid dielectrics 161Bibliography 185Appendix 1 List of Figures 187Appendix 2 List of Symbols 193Appendix 3 List of Useful Values 197Appendix 4 Reminder about Dielectric Spectroscopy 199Appendix 5 Reminder about Transitory Currents 201The Authors 203Index 205

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