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i Plasma Science From Fundamental Research to Technological Applications Panel on Opportunities in Plasma Science and Technology Plasma Science Committee Board on Physics and Astronomy Commission on Physical Sciences, Mathematics, and Applications National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1995
ii NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sci- ences, the National Academy of Engineering, and the Institute of Medicine. This project was supported by the Department of Energy under Contract No. DE- FG05-88ER53279, the National Science Foundation under Grant No. PHY-9100105, and the Office of Naval Research under Contract No. N00014-J-1728. Library of Congress Catalog Card No. 94-69693 International Standard Book No. 0-309-05231-9 Cover: A snapshot of the electron density distribution in a magnetized, pure-electron plasma. These plasmas are nearly ideal, inviscid, two-dimensional fluids and are being used to study the relaxation and self-organization of fluid turbulence (see Plate 2 for details). (Courtesy of C.F. Driscoll, Univer- sity of California, San Diego.) Additional copies of this report are available from: National Academy Press 2101 Constitution Avenue, NW Box 285 Washington, DC 20055 800-624-6242 202-334-3313 (in the Washington Metropolitan Area) Copyright 1995 by the National Academy of Sciences. All rights reserved. Printed in the United States of America
iii PANEL ON OPPORTUNITIES IN PLASMA SCIENCE AND TECHNOLOGY CLIFFORD SURKO, University of California, San Diego, Co-Chair JOHN AHEARNE, Sigma Xi, The Scientific Research Society, Co-Chair PETER BANKS, University of Michigan THOMAS BIRMINGHAM, NASA Goddard Space Flight Center MICHAEL BOYLE, Bondtronix, Inc. RONALD C. DAVIDSON, Princeton University JONAH JACOB, Science Research Laboratory, Inc. MIKLOS PORKOLAB, Massachusetts Institute of Technology EDWIN SALPETER, Cornell University ROBERTA SAXON, SRI International SAM TREIMAN, Princeton University HERBERT YORK, University of California, San Diego (retired) ELLEN ZWEIBEL, University of Colorado RONALD D. TAYLOR, Senior Program Officer (1992â1994) DANIEL F. MORGAN, Program Officer
iv PLASMA SCIENCE COMMITTEE RAVI SUDAN, Cornell University, Chair RICHARD A. GOTTSCHO, AT&T Bell Laboratories, Vice Chair STEVEN C. COWLEY, University of California, Los Angeles JAMES DAKIN, GE Lighting ROY GOULD, California Institute of Technology RICHARD D. HAZELTINE, University of Texas at Austin MARY KATHERINE HUDSON, Dartmouth College WILLIAM L. KRUER, Lawrence Livermore National Laboratory MICHAEL LIEBERMAN, University of California, Berkeley CHUAN S. LIU, University of Maryland NATHAN RYNN, University of California, Irvine ELLEN ZWEIBEL, University of Colorado Former Members of the Committee Who Were ActiveDuring the Period of the Study JONATHAN ARONS, University of California, Berkeley MAHA ASHOUR-ABDALLA, University of California, Los Angeles IRA BERNSTEIN, Yale University E.M. CAMPBELL, Lawrence Livermore National Laboratory RONALD C. DAVIDSON, Princeton University ALAN GARSCADDEN, Wright Research and Development Center ROBERT L. McCRORY, JR., University of Rochester FRANCIS W. PERKINS, Princeton University JOSEPH PROUD, GTE Laboratories Incorporated NORMAN ROSTOKER, University of California, Irvine RONALD D. TAYLOR, Senior Program Officer (1992â1994) DANIEL F. MORGAN, Program Officer
v BOARD ON PHYSICS AND ASTRONOMY DAVID N. SCHRAMM, University of Chicago, Chair ROBERT C. DYNES, University of California, San Diego, Vice Chair LLOYD ARMSTRONG, JR., University of Southern California DAVID H. AUSTON, Rice University DAVID E. BALDWIN, Lawrence Livermore National Laboratory PRAVEEN CHAUDHARI, IBM T.J. Watson Research Center FRANK DRAKE, University of California, Santa Cruz HANS FRAUENFELDER, Los Alamos National Laboratory JEROME I. FRIEDMAN, Massachusetts Institute of Technology MARGARET J. GELLER, Harvard-Smithsonian Center for Astrophysics MARTHA P. HAYNES, Cornell University WILLIAM KLEMPERER, Harvard University AL NARATH, Sandia National Laboratories JOSEPH M. PROUD, GTE Corporation (retired) ROBERT C. RICHARDSON, Cornell University JOHANNA STACHEL, State University of New York at Stony Brook DAVID WILKINSON, Princeton University SIDNEY WOLFF, National Optical Astronomy Observatories DONALD C. SHAPERO, Director ROBERT L. RIEMER, Associate Director DANIEL F. MORGAN, Program Officer NATASHA CASEY, Senior Administrative Associate STEPHANIE Y. SMITH, Project Assistant
vi COMMISSION ON PHYSICAL SCIENCES, MATHEMATICS, AND APPLICATIONS RICHARD N. ZARE, Stanford University, Chair RICHARD S. NICHOLSON, American Association for the Advancement of Science, Vice Chair STEPHEN L. ADLER, Institute for Advanced Study, Princeton SYLVIA T. CEYER, Massachusetts Institute of Technology SUSAN L. GRAHAM, University of California, Berkeley ROBERT J. HERMANN, United Technologies Corporation RHONDA J. HUGHES, Bryn Mawr College SHIRLEY A. JACKSON, Rutgers University KENNETH I. KELLERMANN, National Radio Astronomy Observatory HANS MARK, University of Texas at Austin THOMAS A. PRINCE, California Institute of Technology JEROME SACKS, National Institute of Statistical Sciences L.E. SCRIVEN, University of Minnesota LEON K. SILVER, California Institute of Technology CHARLES P. SLICHTER, University of Illinois at Urbana-Champaign ALVIN W. TRIVELPIECE, Oak Ridge National Laboratory SHMUEL WINOGRAD, IBM T.J. Watson Research Center CHARLES A. ZRAKET, Mitre Corporation (retired) NORMAN METZGER, Executive Director
vii Preface In the mid-1980s, the plasma physics volume of the series PhysicsThrough the 1990s (National Research Council, National Academy Press, Washington, D.C., 1986) signaled problems for plasma science in the United States, particularly with regard to the basic aspects of the science. In the years that followed, there developed a widespread feeling in the plasma science community that something systematic needed to be done to address these issues. Out of this concern, the Plasma Science Committee of the Board on Physics and Astronomy was created in 1988. Following its establishment, plans were begun to undertake this study. With funding from the National Science Foundation, the Department of Energy, and the Office of Naval Research, the Panel on Opportunities in Plasma Science and Technology was appointed in May 1992, and the study began. Approximately half of the 13-member panel consisted of experts in the many facets of plasma science considered in this report and half of scientists outside the field, with one of the co-chairs selected as a person with experience in science policy. Three of the members are from industry; one is from a government laboratory and one from an independent research society; and the remaining eight are from academe. The task statement to the panel requested that this study examine virtually all aspects of plasma science and technology in the United States, assess the health of basic plasma science as a research enterprise, and identify and address key issues in the field. Specifically, the panel was charged with the task of conducting an assessment of plasma science that included beams, accelerators, and coherent radiation sources; single-species plasmas and atomic traps; basic plasma science in magnetic confinement and inertial fusion devices; space plasma
viii physics; astrophysics; low-temperature plasmas; and theoretical and computational plasma science. It was directed to address the following: 1. Assess the health of basic plasma science in the United States as a research enterprise: (a) Identify and describe selected scientific opportunities. (b) Identify and describe selected technological opportunities. (c) Assess and prioritize new opportunities for research using the criteria of intellectual challenge, prospects for illumination of classic research questions, connection with other fields of science, and potential for applications. (d) Assess applications using the criteria of potential for contributing to industrial competitiveness, national defense, human health, and other aspects of human welfare. 2. Identify and address the issues in the field, including the following: (a) Evaluate the quality and size of the educational programs in plasma science in light of the nation's future needs. (b) Assess the institutional infrastructure in which plasma science is conducted, and identify changes that would improve the research and educational effort. (c) Characterize the basic experimental facilities needed to increase scientific productivity. (d) Develop a research strategy that is responsive to the issues. (e) Compare the U.S. program with those of Japan and Western Europe, and identify opportunities for international cooperation. (f) Identify the interactions and synergism with other areas of physics, chemistry, mathematics, and astronomy. (g) Assess the linkage of theory and experiment. (h) Assess manpower requirements and the prospects for meeting them. (i) Identify the users of plasma science and their needs. 3. Make recommendations to federal agencies and to the community that address these issues. During the course of the study, the panel held three two-day meetings and two lengthy teleconferences. As part of the process, the panel took steps to solicit input from the plasma science community. Letters were sent to 200 scientists and engineers, requesting their input on the issues raised in the charge to the panel. This list was selected from the list of Fellows of the Plasma Physics Division of the American Physical Society (90), and it also included others suggested by members of the panel (65) and by grant officers involved in funding plasma science (45). The letters went to university faculty and staff (90), industrial scientists (25), staff at national laboratories (50), and others (5). A separate, more specialized survey was sent to 33 experimentalists engaged in basic plasma physics research. Input was also solicited by announcements of the panel's work that appeared in the newsletters of the American Geophysical Union, the American Physical Society, the Plasma Physics Division of the American Physical Society, the Committee on Plasma Science of the Institute of Electrical and Electronics Engineers (IEEE), and the University Fusion Associates. Town meetings were held at American Physical Society Plasma Physics Division meetings and the Gaseous Electronics Conference. There is general agreement from these
ix sources on the themes expressed in this report: There is concern about the decline in basic plasma science, particularly in the area of basic plasma experimentation and other small-scale research efforts, and basic plasma science is perceived to lack a "home" in the federal agencies. Also during the course of the study, the panel heard presentations from grant officers involved in funding plasma science from the Air Force Office of Scientific Research, the Advanced Research Projects Agency, the Department of Energy, the National Aeronautics and Space Administration, the National Science Foundation, and the Office of Naval Research. The task statement requested that the panel assess specific areas of plasma science, such as beams, accelerators, and coherent radiation sources (called topical areas in the report), and broad areas ofplasma science, including fundamental plasma experiments, theoretical and computational plasma physics, and education in plasma science. At the first meeting of the panel, these areas were renamed slightly and the topical area of low-temperature plasmas was added, since it had been omitted from the task statement through an oversight. The resulting seven topical areas are assessed in Part II of the report, and the three broad areas of plasma science are assessed in Part III. Part IV consists of some concluding remarks. During the course of the study, the panel had numerous discussions about the desirability of establishing organizational units specifically devoted to plasma science in the relevant federal agencies. Many members of the plasma science community who were consulted strongly advocated the establishment of such homes, believing that they are needed if basic plasma science is to be given the focused attention and increased support that the panel recommends. While this subject is beyond the scope of the panel's work, the panel suggests that the federal government might give this issue further consideration.
xi Acknowledgments In preparing this report, the Panel on Opportunities in Plasma Science and Technology has benefited greatly from the assistance of many members of the plasma science community. We are particularly indebted to the former chairs of the Plasma Science Committee of the Board on Physics and Astronomy, C.F. Kennel and F.W. Perkins, and the present chair, Ravi Sudan, for their advice and help. The other members of the Plasma Science Committee also provided valuable advice during the course of the study. The panel would like to acknowledge the following colleagues for the extensive advice and assistance they provided in assembling the broad range of material covered in this report and for critical reading of various portions of it: Jonathan Arons, University of California, Berkeley; Ira B. Bernstein, Yale University; John Bollinger, National Institute of Standards and Technology, Boulder, Colorado; Keith H. Burrell, GA Technologies, Inc.; Vincent S. Chan, GA Technologies, Inc.; Xing Chen, Science Research Laboratory, Inc.; Samuel A. Cohen, Princeton Plasma Physics Laboratory; Bruce Danly, Plasma Fusion Center, Massachusetts Institute of Technology; Luiz Da Silva, Lawrence Livermore National Laboratory; Patrick Diamond, University of California, San Diego; Paul Drake, Lawrence Livermore National Laboratory; C. Fred Driscoll, University of California, San Diego; Eduardo Epperlein, University of Rochester Laboratory for Laser Energetics; Joel Fajans, University of California, Berkeley; Walter Gekelman, University of California, Los Angeles; Brian Gilchrist, University of Michigan; Martin Goldman, University of Colorado; Tamas I. Gombosi, University of Michigan; Daniel Goodman, Science Research Laboratory, Inc.; Richard A. Gottscho, AT&T Bell Laboratories; Roy W. Gould, California Institute of Technology; Hans Griem, University of Maryland; Larry R. Grisham, Princeton
xii Plasma Physics Laboratory; Richard Hazeltine, University of Texas; Noah Hershkowitz, University of Wisconsin; Chuck Hooper, University of Florida; Mary Hudson, Dartmouth College; Chandrashekhar Joshi, University of California, Los Angeles; Robert Kessler, Textron Defense Systems; William Kruer, Lawrence Livermore National Laboratory; Stephen Lane, Lawrence Livermore National Laboratory; Richard Lee, Lawrence Livermore National Laboratory; Bruce Lipschultz, Plasma Fusion Center, Massachusetts Institute of Technology; James F. Lyon, Oak Ridge National Laboratory; James Maggs, University of California, Los Angeles; Earl S. Marmar, Plasma Fusion Center, Massachusetts Institute of Technology; Dennis Mathews, Lawrence Livermore National Laboratory; Jakob Maya, Matsushita Electrical Works, R&D Laboratory; Kevin M. McGuire, Princeton Plasma Physics Laboratory; George Morales, University of California, Los Angeles; Andrew Nagy, University of Michigan; Torsten Neubert, University of Michigan; Francis W. Perkins, Princeton Plasma Physics Laboratory; Arthur V. Phelps, JILA, University of Colorado (retired); Stewart C. Prager, University of Wisconsin; Juan Ramirez, Sandia National Laboratories; Barrett Ripin, American Physical Society; Gerald L. Rogoff, Sylvania, Inc.; Louis Rosocha, Los Alamos National Laboratory; Norman Rostoker, University of California, Los Angeles; Andrew Schmitt, Naval Research Laboratory; Wolf Seka, University of Rochester Laboratory for Laser Energetics; Gary Selwyn, Los Alamos National Laboratory; Frederick Skiff, University of Maryland; Reiner Stenzel, University of California, Los Angeles; Raul Stern, University of Colorado, Boulder; Ravindra Sudan, Cornell University; Roscoe White, Princeton Plasma Physics Laboratory; Scott Wilks, Lawrence Livermore National Laboratory; David Wineland, National Institute of Standards and Technology, Boulder, Colorado; Masaaki Yamada, Princeton Plasma Physics Laboratory; Michael C. Zarnstorff, Princeton Plasma Physics Laboratory.
CONTENTS xiii Contents Executive Summary 1 PART I: OVERVIEW Introduction 7 The Role of Plasma Science in Our Society 8 The Discipline of Plasma Science 11 Common Research Themes 11 Wave-Particle Interactions and Plasma Heating 11 Chaos, Turbulence, and Transport 14 Plasma Sheaths and Boundary Layers 14 Magnetic Reconnection and Dynamo Action 14 Research and Education in Plasma Science 15 Basic Plasma Experiments 15 Theory and Computational Plasma Physics 17 Education in Plasma Science 18 Summary of Topical Areas 19 Low-Temperature Plasmas 19 Nonneutral Plasmas 20 Inertial Confinement Fusion 21 Magnetic Confinement Fusion 22
CONTENTS xiv Beams, Accelerators, and Coherent Radiation Sources 24 Space Plasmas 24 Astrophysical Plasmas 26 Central Messages of this Report 26 Conclusions and Recommendations 28 PART II: TOPICAL AREAS 1 Low-Temperature Plasmas 33 Introduction 33 Lighting 36 Gas Discharge Lasers 37 Plasma Isotope Separation 38 Plasmas for Electric Propulsion of Space Vehicles 39 Magnetohydrodynamics 39 Plasmas for Pollution Control and Reduction 40 Plasma Processing of Materials 42 Conclusions and Recommendations 45 Conclusions 45 Recommendations 45 2 Nonneutral Plasmas 47 Introduction and Background 47 Recent Advances in Nonneutral Plasmas 48 Electron Plasmas 49 Ion Plasmas 50 Ion Plasmas in Electron-Beam Ion Traps 51 Confinement of Antimatter 53 Research Opportunities 53 Coherent Structures and Vortex Dynamics 54 Transport Processes 54 Confinement Properties in Nonaxisymmetric Geome- 54 tries Stochastic Effects 54 Strongly Coupled Nonneutral Plasmas 55 Quantum-Mechanical Effects 56 Antimatter 56 Opportunities for Advances in Technology 57 Precision Clocks 57 Precision Mass Spectrometry 57 Ion Sources with Enhanced Brightness 57
CONTENTS xv Electron-Beam Ion Traps 58 Radiation Sources 58 Pressure Standard in Ultrahigh-Vacuum Regime 58 Summary, Conclusions, and Recommendations 59 3 Inertial Confinement Fusion 60 Introduction and Background 60 Recent Advances 61 Laser Fusion 61 Ion-Beam Fusion 62 Scientific and Technological Opportunities 64 Conclusions and Recommendations 69 4 Magnetic Confinement Fusion 71 Introduction 71 Magnetohydrodynamics and Stability 72 Introduction and Background 72 Past Achievements 72 Future Prospects 73 Tokamak Transport 74 Introduction and Background 74 Past Achievements 74 Future Prospects 75 Edge and Divertor Physics 77 Introduction and Background 77 Recent Advances 79 Future Research and Technical Opportunities 79 Plasma Heating and Non-inductive Current Drive 80 Neutral-Beam Heating and Current Drive 80 Introduction and Background 80 Past Achievements 81 Future Prospects 81 Radio-Frequency Heating and Current Drive 81 Introduction and Background 81 Past Achievements 83 Future Prospects 83 Diagnostic Development 84 Introduction and Background 84 Past Achievements 84 Future Prospects 86 Non-Tokamak Concepts 86 Introduction and Background 86 Recent Advances 87
CONTENTS xvi Future Prospects 88 Conclusions 89 Recommendations 90 5 Beams, Accelerators, and Coherent Radiation Sources 92 Introduction and Background 92 Recent Advances and Science and Technology Oppor- 92 tunities Intense Charged-Particle Beams 92 Accelerators 94 Coherent Radiation Sources 96 Conclusions and Recommendations 98 6 Space Plasmas 100 Introduction 100 Background 100 Status 101 Tools for Space Plasma Physics 103 Space-Based Techniques 103 Ground-Based Techniques 103 Plasma Theory and Simulations 105 Laboratory Techniques 106 Fundamental Processes in Space Plasmas 106 Wave-Particle Interactions 106 Charged-Particle and Plasma Energization 107 Dust-Plasma Interactions 108 The Critical Ionization Velocity Effect 108 Radiation Processes 109 Active Experiments 109 Plasma and Neutral Mass Injections 109 Particle Beam Experiments 110 Wave Injection Experiments 110 Vehicle-Environment Interactions 111 Future Plans and Opportunities 112 In Situ Observations 112 In Situ Experiments 116 Terrestrial Observation Networks 116 Laboratory Experiments 117 Conclusions and Recommendations 118 7 Plasma Astrophysics 120 Recent Accomplishments in Plasma Astrophysics 120 Magnetized Disks, Winds, and Jets 120 Particle Acceleration in Shocks 121
CONTENTS xvii Magnetized Convection in Stars 121 Formation of Low-Mass Stars 121 Problems in Plasma Astrophysics 123 Dense Stellar Plasmas 123 Thermal Conduction in Plasmas 123 Structure of Collisionless Shocks 123 Acceleration of Particles to High Energies 124 Hydromagnetic Turbulence 124 Magnetic Reconnection 124 The Magnetization of the Universe 125 Laboratory Experiments 125 Training in Plasma Astrophysics 125 Funding for Plasma Astrophysics 126 Summary 127 Conclusions and Recommendations 127 Conclusions 127 Recommendation 127 PART III: BROAD AREAS OF PLASMA SCIENCE 8 Basic Plasma Experiments 131 Introduction and Background 131 Overview of Recent Progress 133 Basic Plasma Experiments 133 Wave Phenomena 133 Bernstein Waves 133 Mode Conversion 134 Wave-Particle Interactions 134 Magnetically Trapped Particle Instabilities 134 Lower Hybrid Wave Current Drive 135 Beat Wave Excitation and Particle Acceleration 135 Nonlinear Phenomena 135 Double Layers 135 Ponderomotive Forces and the Filamentation of 135 Electromagnetic Radiation Magnetic Field Line Reconnection 136 Plasma Reorganization 136 Chaos and Turbulence 137 Chaos 137 Quasilinear Effects and Single-Wave Stochastic- 137 ity Collisionless Heat Transport 139 Strong Langmuir Turbulence 139 Experimental Techniques and Capabilities 139 Plasma Sources 139 Mechanical Probes 141
CONTENTS xviii Laser-Based Optical Diagnostics 142 Data Acquisition and Processing 143 Research Opportunities 144 Fundamental Plasma Processes 144 Wave Phenomena 144 AlfvÃ©n Waves 144 Wave-Plasma Interactions 144 Intense Laser-Plasma Interactions 144 Chaos, Turbulence, and Localized Structures 145 Nonlinear Particle Dynamics and Chaos 145 Nonlinear Wave Phenomena 145 Turbulence 145 Turbulent Transport 146 Sheaths, Boundary Layers, and Double Layers 146 Shock Waves 147 Striated Plasmas 147 Flows in Magnetized Plasmas 147 Plasmoids 147 Magnetic Effects 148 Magnetic Field Line Reconnection 148 Dynamo Action 148 Magnetic Reconfiguration 149 New Experimental Capabilities 150 Use of Nanotechnology 150 Optical Diagnostics 150 New Regimes of Plasma Parameters 151 Data Acquisition 151 Massively Parallel Plasma Diagnostics 151 Summary, Conclusions, and Recommendations 152 9 Theoretical and Computational Plasma Physics 156 Introduction and Background 156 Recent Advances in Theoretical and Computational 159 Plasma Physics Hamiltonian Transport 159 Coherent Structures and Self-Organization 160 Strong Plasma Turbulence 160 Gyrokinetics 160 Large-Orbit Effects on Plasma Stability 161 Three-Dimensional Magnetohydrodynamics 161 Numerical Simulation of Plasma Processes 161 Nonlinear Laser-Plasma Interaction 161 Nonlinear Processes in Ionospheric Plasmas 162 Collisional Relaxation of Nonneutral Plasmas 162 Free-Electron Lasers and High-Power Microwave 163 Sources Research Opportunities 163 Basic Plasma Theory and Applications to Labora- 163 tory Plasmas
CONTENTS xix Nonlinear Plasma Processes 163 Numerical Simulation 164 Novel Analytical Techniques 164 Boundary Layers 164 Kinetic Theory 165 Stochastic Effects in Evolving Plasmas 165 Alpha-Particle Effects in Magnetically Confined 165 Plasmas Concept Improvement 166 Nonlinear Interaction of Intense Electromagnetic 166 Waves with Plasmas Current-Carrying Plasmas with Flow 167 Engineering Design Tools 167 Space Plasmas 167 Magnetic Reconnection 168 Turbulence 168 Large-Scale Flows 169 Particle Acceleration 169 Plasma Confinement and Transport 170 Collisionless Shocks 171 Chaotic Effects 171 Summary 172 Conclusions and Recommendations 172 10 Education in Plasma Science 174 Degree Production and Employment Statistics 174 Estimate of Future Supply of Plasma Physicists 177 Educating Non-Plasma Students in Plasma Physics 178 General Comments 178 Recommendations 180 PART IV: CONCLUSION APPENDICES A Federal Funding Data 189 B Letters to Funding Agencies 193 C List of Agencies Contacted 199
xxi Plasma Science From Fundamental Research to Technological Applications