The Fourth State of Matter An Introduction to Plasma Science Second Edition Shalom Eliezer Plasma Physics Department Soreq Nuclear Research Center Yavne, Israel and Yaffa Eliezer Weizmann Institute of Science Rehovot, Israel Institute of Physics Publishing Bristol and Philadelphia IOP Publishing Ltd 2001 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publisher. Multiple copying is permitted in accordance with the terms of licences issued by the Copyright Licensing Agency under the terms of its agreement with the Committee of Vice-Chancellors and Principals. British Library Cataloguing-in-Publication Data A catalogue record of this book is available from the British Library. ISBN 0 7503 0740 4 Library of Congress Cataloging-in-Publication Data are available First edition 1989 Commissioning Editor: John Navas Production Editor: Simon Laurenson Production Control: Sarah Plenty Cover Design: Fre´de´rique Swist Marketing Executive: Colin Fenton Published by Institute of Physics Publishing, wholly owned by The Institute of Physics, London Institute of Physics Publishing, Dirac House, Temple Back, Bristol BS1 6BE, UK US Office: Institute of Physics Publishing, The Public Ledger Building, Suite 1035, 150 South Independence Mall West, Philadelphia, PA 19106, USA Typeset by Academic þ Technical, Bristol Printed in the UK by J W Arrowsmith Ltd, Bristol Dedication To our four children, Yosi, Lori, Orit and Dalya, their spouses and all our grandchildren. Where there is no vision, the people perish Book of Proverbs, Chapter 29, 18. Contents Foreword to the Second Edition xi Acknowledgments xii Prologue 1 1 Highlights to Plasma 5 1.1 Unveiling Matter 5 1.2 Unveiling the Atom 7 1.3 Unveiling the Electron 12 1.4 Unveiling the Nucleus 16 1.5 Unveiling a New State of Matter 21 2 What is Plasma? 22 2.1 Introducing Plasma 22 2.2 A Visit to an Exotic Nightclub 26 2.3 A Joint Ping-Pong Game 27 2.4 The One-Mile Run 29 2.5 Shielding 33 2.6 Collisions 34 2.7 Swallowing and Ejecting Photons 37 2.8 The Agents 39 2.9 Safekeeping 43 2.10 Plasma Reflections 44 2.11 Plasma Compendium 47 3 A Universe of Plasma 49 3.1 Plasma in the Beginning 49 3.2 The Universe 52 3.3 The Magnetosphere 56 3.4 Light From the Stars 60 3.5 The Star’s Interior 63 3.6 The Solar Exterior 66 viii CONTENTS 3.7 A Supernova Explosion 70 3.8 Synchrotron Radiation 72 3.9 Comets 75 3.10 From the Visual to the Plasma Universe 76 4 Plasma in Industry 79 4.1 Understanding Plasma for Application in Industry 79 4.2 Semiconductor Electronics 86 4.3 Plasma Modification of Materials 87 4.4 Plasma Spray 89 4.5 Plasma Welding, Cutting and Material Processing 92 4.6 Plasma Space Propulsion 93 4.7 Plasma Display Panels 94 4.8 Plasma and the Diamond Industry 94 4.9 Plasma and Treating Wastes 95 4.10 Plasma Lighting 96 4.11 Particle Accelerators and Plasma 98 4.12 X-Ray Lasers 99 4.13 Plasma Isotope Separation 100 4.14 Plasma Antennas 101 4.15 More Efficient, Unique, More Environmentally Clean 101 5 The Solution to the Energy Problem 103 5.1 Soylent Green 103 5.2 World Energy Consumption 106 5.3 Nuclear Energy 107 5.4 Nuclear Fusion Energy 108 5.5 Conditions for Nuclear Fusion 115 5.6 Ignition Temperature 118 5.7 Magnetic Confinement—Magnetic Bottles 119 5.8 Plasma Diffusion 120 5.9 Plasma Instabilities 122 5.10 Plasma Formation 124 5.11 Plasma Heating 124 5.12 The Tokamak 126 5.13 Magnetic Mirrors 129 5.14 Nuclear Fusion Reactors 130 5.15 Inertial Confinement with Lasers 132 5.16 Particle Beam Fusion 142 5.17 Advantages of Nuclear Fusion Energy 143 5.18 The Transition to the Fusion Era 144 5.19 TFTR, JET and other Magnetic Fusion Devices 147 5.20 Indirect Drive for Inertial Fusion Energy 149 5.21 Fast Ignitors 151 CONTENTS ix 5.22 The Z-Pinch 152 5.23 Outlook 153 6 . More History of Plasma Physics 154 6.1 Plasma Without Realization 154 6.2 Realizing the Fourth State of Matter—Plasma 155 6.3 Controlled Lightning 157 6.4 The Ionosphere—A Plasma Mirror for Radio Signals 159 6.5 Plasma in Space 160 6.6 The Sun’s ‘Secret’ Source of Energy 161 6.7 Splitting the Atom—Fission 162 6.8 Fusion—The Synthesis of Light Nuclei 163 6.9 Solving the Energy Problem for the Generations Ahead 165 6.10 The Beginning of Controlled Nuclear Fusion in the USA 166 6.11 The Beginning of Nuclear Fusion in Britain and the Soviet Union 168 6.12 International Declassification of Controlled Nuclear Fusion 169 6.13 Landmarks in the Development of Plasma Physics 171 Appendix: Rhyming Verses 175 Epilogue 191 Glossary 193 Bibliography 210 Index 215 Foreword to the Second Edition To invade The Fourth State of Matter and to present it in a popular com- prehensive book is not an easy task. This might explain why very few, if any, popular books on plasma science are available on the market today. Books of this type are not only interesting but also very useful to the gen- eral public as well as to students, engineers and scientists. To our satisfac- tion the first edition is still being cited on the Internet by leading prominent web sources such as Encyclopedia Britannica and NASA. After the first edition was sold out we received many requests for copies of the book. The above encouraged us to write the second edition of The Fourth State of Matter. The aim of the second edition is to bring The Fourth State of Matter up to date in the light of progress. Sometimes progress is almost insignificant in ten years and sometimes, as in the field of plasmas, it is immense. The second edition includes a multitude of new discoveries and applications. A new chapter on ‘plasma in industry’ is added and all other chapters are updated and enlarged. A history of plasma is described throughout the book and summarized in a separate chapter. A bibliography has also been added. This edition contains almost all aspects of plasma science, plasma in space, industrial and energy applications. The second edition is a nonmathematical book that can be read with negligible previous knowledge of physics. It is not necessary to ‘speak physics’ to understand and enjoy it. Yaffa and Shalom Eliezer Rehovot January 2001 Acknowledgments We would like to thank Dr Yehuda Paiss for an exchange of valuable and exciting discussions. His critical reading of the new chapter on plasma in industry is also greatly appreciated. Special thanks to Edo Dekel for his good advice and help with the technical problems in preparing the manuscript. Prologue When my daughter, Lori, began to study physics in high school, she very soon became frustrated and confused with the subject. My husband, who is a physicist and co-author of this book, spent many hours helping her with her studies and tried to impress upon her the importance and necessity of learning this fundamental subject. He tried patiently to explain the complicated formulas in a simplified manner. At the same time he included some pictorial and easy-to-remember comparisons with events of everyday life and some background history and ‘gossip’ in order to make the subject more captivating and comprehensible. I, myself, who had never studied physics, sympathized with her and could well under- stand her frustration and irritation as I watched them work out some lengthy and complicated problems on paper. Still, I found myself eaves- dropping on his simple comparisons and amusing ‘gossip’. My first encounter with baffling terminology and complicated and lengthy equations was when I was hired as an English typist at a research center. Later, when I became the secretary to the Plasma Physics Depart- ment, my husband, who was at that time the head of the department and my boss, spent many hours explaining some of the experiments and basic principles of physics to me. I was also fortunate to work with some very interesting and clever scientists who patiently explained their compli- cated research to me. Although they tried to stress to me the beauty, romance, excitement and importance of their work, I’m afraid that they failed to excite my curiosity and most of the time I felt excluded from their enthusiasm and involvement. When, a few years later, I married ‘my boss’, the head of the depart- ment, he encouraged me to attend some popular physics lectures and to read some ‘easy’ material on the subject. We would later spend many evenings discussing the various topics. The more he explained, the more I pressed him for more, always insisting that he use ‘simple Eng- lish’. I must admit that at times I monopolized his time and exhausted his stamina. But slowly I became more familiar with some of the terminology and found myself becoming involved in some discussions in which I would not have dared indulge in the past. I was often flattered when I 2 PROLOGUE met some of my husband’s colleagues and, after an hour of discussion, they asked whether I, too, was a physicist. As secretary to the Plasma Physics Department, I was very surprised at the response I received when I answered the telephone and gave the name of the department.