TRENDS IN ELECTROMAGNETISM – FROM FUNDAMENTALS TO APPLICATIONS Edited by Victor Barsan and Radu P. Lungu Trends in Electromagnetism – From Fundamentals to Applications Edited by Victor Barsan and Radu P. Lungu Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Maja Jukic Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published March, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechopen.com Trends in Electromagnetism – From Fundamentals to Applications, Edited by Victor Barsan and Radu P. Lungu p. cm. ISBN 978-953-51-0267-0 Contents Preface IX Part 1 Fundamentals 1 Chapter 1 Current-Carrying Wires and Special Relativity 3 Paul van Kampen Chapter 2 Reformulation of Electromagnetism with Differential Forms 21 Masao Kitano Chapter 3 Foundations of Electromagnetism, Equivalence Principles and Cosmic Interactions 45 Wei-Tou Ni Part 2 Electromagnetism, Thermodynamics and Quantum Physics 69 Chapter 4 Topological Electromagnetism: Knots and Quantization Rules 71 Manuel Arrayás, José L. Trueba and Antonio F. Rañada Chapter 5 Waveguides, Resonant Cavities, Optical Fibers and Their Quantum Counterparts 89 Victor Barsan Chapter 6 Thermodynamics of Electric and Magnetic Systems 113 Radu Paul Lungu Part 3 Numerical Methods in Electromagnetism 153 Chapter 7 Fast Preconditioned Krylov Methods for Boundary Integral Equations in Electromagnetic Scattering 155 Bruno Carpentieri Chapter 8 Time Reversal for Electromagnetism: Applications in Electromagnetic Compatibility 177 Ibrahim El Baba, Sébastien Lalléchère and Pierre Bonnet VI Contents Chapter 9 Three-Dimensional Numerical Analyses on Liquid-Metal Magnetohydrodynamic Flow Through Circular Pipe in Magnetic-Field Outlet-Region 207 Hiroshige Kumamaru, Kazuhiro Itoh and Yuji Shimogonya Part 4 Technological and Engineering Applications 223 Chapter 10 Magnetic Refrigeration Technology at Room Temperature 225 Houssem Rafik El-Hana Bouchekara and Mouaaz Nahas Chapter 11 Coupled-Line Couplers Based on the Composite Right/Left-Handed (CRLH) Transmission Lines 251 Masoud Movahhedi and Rasool Keshavarz Chapter 12 Theory and Applications of Metamaterial Covers 277 Mehdi Veysi, Amir Jafargholi and Manouchehr Kamyab Preface A century and a half after the formulation of Maxwell’s equations, electromagnetism is a domain in spectacular expansion, incorporating continuously the progress in fundamental and applicative physics, from relativity to materials science, and responding, in this way, to the challenges of the modern world. The present book provides 12 review papers on recent developments in electromagnetism, from fundamentals to electrical engineering. They are grouped in four sections, as follows. The first one covers fundamental problems of electromagnetic theory. In van Kampen’s paper, linear charge and currents distributions make possible to introduce the main concepts of electromagnetism without use of vector calculus. Special relativity is invoked to demonstrate that electricity and magnetism are, in a sense, two different ways of looking at the same phenomenon: in principle, from either electricity or magnetism and special relativity, the third theory could be derived. Starting with the standard Maxwell’s equations, Ni’s paper presents the different types of quantum corrections, and the corresponding equations for nonlinear electrodynamics. The electromagnetism in curved spaces and the Einstein equivalence principle, together with the different experimental results for the cosmic polarization rotation, are discussed. In his chapter, Kitano reformulates the electromagnetic theory using differential forms, by taking into consideration the physical perspective, the unit system (physical dimensions), and the geometrical aspects. In this way, he provides a unified, clear and original view of electromagnetism. The second section is devoted to the interconnections between electromagnetism and quantum and thermal physics. The topological model of electromagnetism constructed with electromagnetic knots is presented in Ranada’s paper. It puts in a new light the classical and quantum aspects X Preface of the electromagnetic theory, treats electricity and magnetism symmetrically, and gives a theoretical explanation for the quantization of the magnetic flux in superconductors. As the time-independent wave equations for the classical electric and magnetic field, and for the wave function for a quantum particle, are similar, an interesting analogy can be developed between electromagnetic wave propagation in waveguides, ballistic electron transport in mesoscopic conductors and light propagation in optical fibres. These issues are addressed in Barsan’s review. In Lungu’s review, the different types of the thermodynamic potentials of electric and magnetic systems are rigorously derived, starting from the principles of thermodynamics and Maxwell equations. From the general expressions of the potentials, the equations of state and the thermodynamic coefficients are deduced. Finally, using the results previously obtained, some important thermodynamic processes are discussed. The next section puts together three important problems of electromagnetism – scattering of electromagnetic waves, electromagnetic compatibility and liquid metal flow in strong magnetic fields - treated with numerical methods. An accurate numerical solution of electromagnetic scattering problems is critically demanded in the simulation of industrial processes and in the study of wave propagation phenomena. Modern techniques use the integral equations to reformulate Maxwell’s equations for electric and magnetic fields on the surface of the object. These equations are solved in Carpentieri’s contribution, using recent progress in numerical analysis. The electromagnetic compatibility, i.e. the need of avoiding undesirable effects of electromagnetic interference due to the simultaneous functioning of several electric devices in the same area, is addressed in El Baba’s paper. The backward propagation of electromagnetic waves, based on the time reversal invariance of the electromagnetic wave equation, is the starting point of a detailed numerical study of the parasitic electromagnetic fields, in various geometries and environments. Exact characterization of the liquid-metal lithium passing through a strong magnetic field, which is used in order to confine the high-temperature reacting plasma in a fusion reactor core, is essential for the evaluation of the heat transfer in such a complex device. A 3D calculation is crucial for the precise evaluation of magneto-hydro- dynamic flow in the inlet or outlet region of the magnetic field. Such a calculation, attentively discussed and interpreted, is presented in Kumamuru’s chapter. The last section is devoted to applicative issues, starting with magnetic refrigeration technology at room temperature. The ultimate goal of this emerging technology is to develop a standard refrigerator for home use, using the magnetocaloric effect. Bouchekara’s chapter describes the magnetic refrigeration technology, from modern . TRENDS IN ELECTROMAGNETISM – FROM FUNDAMENTALS TO APPLICATIONS Edited by Victor Barsan and Radu P. Lungu Trends in Electromagnetism – From Fundamentals to Applications. free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechopen.com Trends in Electromagnetism – From Fundamentals to Applications, . (2) 4 Trends in Electromagnetism – From Fundamentals to Applications Current-Carrying Wires and Special Relativity 3 and for the field due to a point charge Q, E = 1 4π 0 Q r 2 ˆ r. (3) Finally,