Plasma physics : an introduction to laboratory, space, and fusion plasmas

473 Pages·2017·17.15 MB·English

Graduate Texts in Physics
Alexander Piel
Plasma Physics
An Introduction to Laboratory,
Space, and Fusion Plasmas
Second Edition
Graduate Texts in Physics
Series editors
Kurt H. Becker, Polytechnic School of Engineering, Brooklyn, USA
Jean-Marc Di Meglio, Université Paris Diderot, Paris, France
Sadri Hassani, Illinois State University, Normal, USA
Bill Munro, NTT Basic Research Laboratories, Atsugi, Japan
Richard Needs, University of Cambridge, Cambridge, UK
William T. Rhodes, Florida Atlantic University, Boca Raton, USA
Susan Scott, Australian National University, Acton, Australia
H. Eugene Stanley, Boston University, Boston, USA
Martin Stutzmann, TU München, Garching, Germany
Andreas Wipf, Friedrich-Schiller-Universität Jena, Jena, Germany
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Alexander Piel
Plasma Physics
An Introduction to Laboratory, Space,
and Fusion Plasmas
Second Edition
123
Alexander Piel
Institute for Experimental andApplied
Physics
Kiel University
Kiel
Germany
ISSN 1868-4513 ISSN 1868-4521 (electronic)
Graduate Textsin Physics
ISBN978-3-319-63425-8 ISBN978-3-319-63427-2 (eBook)
DOI 10.1007/978-3-319-63427-2
LibraryofCongressControlNumber:2017950029
1stedition:©Springer-VerlagBerlinHeidelberg2010
2ndedition:©SpringerInternationalPublishingAG2017
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To HANNEMARIE,
CHRISTOPH and JOHANNES
Preface
Feedback from many colleagues has motivated me to prepare the present second
enlarged edition of Plasma Physics. The scope of this book has been extended to
coverrecentdevelopmentsinplasmadevices,toupdatetherapidlyevolvingfieldof
dusty plasmas, and to describe plasma diagnostics in more detail.
Four chapters have been substantially expanded. In Chap. 4, the diffusion pro-
cesses in gas discharges are now introduced by means of random walks, which
illuminate the difference between deterministic motion in external fields and ran-
domprocesses.Chapter7hasbeenreorganizedtoseparategeneralstatementsabout
the plasma-sheath transition from applications in plasma diagnostics. Langmuir
probe diagnostics is now introduced in two steps, beginning with the elementary
theory of plane probes and advancing to the tricks of the trade in probe measure-
ments.Thesecomprisetheinfluenceoflow-frequencyandhigh-frequencyvoltages
on Langmuir probe diagnostics. The passive and active compensation methods for
Langmuir probes in rf discharges are described. In Chap. 10, refined charging
models are discussed. Plasma crystals are described with regard to solid-liquid
phase transitions and the formation of spherical Yukawa balls. The puzzling phe-
nomenonofattractiveforcesfromwakechargingisdiscussedindetail.Chapter11
has a new section on sputtering magnetrons and high-power impulse magnetron
sputtering. The section on capacitive rf discharges has been extended by a dis-
cussion of the recently discovered electrical asymmetry effect.
I thank Nils Brenning, Holger Kersten, André Melzer, and Iris Pilch for their
criticalcommentsontheextendedchapters.EberhardMöbiusandhisstudentsgave
valuable hints at many typos in the first edition. The enthusiasm of my PhD stu-
dents and the patience of my collaborators were essential for the progress in our
dustyplasmaresearch,whichhasbeenincludedinthissecondedition.Again,many
colleagues, journals, and institutions gave kind permission to reproduce figures,
which is gratefully acknowledged. My thanks go to Thorsten Schneider and the
entireSpringerteamforencouragementandprofessionalpreparationofthisedition.
Kiel, Germany Alexander Piel
vii
Preface to the First Edition
ThisbookisanoutgrowthofcoursesinplasmaphysicswhichIhavetaughtatKiel
University for many years. During this time, I have tried to convince my students
that plasmas as different as gas discharges, fusion plasmas, and space plasmas can
be described in a unified way by simple models.
Thechallengeinteachingplasmaphysicsisitsapparentcomplexity.Thewealth
ofplasmaphenomenafoundinsodiversefieldsmakesitquitedifferentfromatomic
physics, where atomic structure, spectral lines, and chemical binding can all be
derived from a single equation—the Schrödinger equation. I positively accept the
varietyofplasmasandrefrainfromsubdividingplasmaphysicsintothetraditional,
butartificiallyseparatedfields,ofhot,cold,andspaceplasmas.ThisiswhyIliketo
confront my students, and the readers of this book, with examples from so many
fields.Bythisapproach,Ibelieve,theywillbeabletobecomediscovererswhocan
see the commonality between a falling apple and planetary motion.
As an experimentalist, I am convinced that plasma physics can be best under-
stood from a bottom-up approach with many illustrating examples that give the
students confidence in their understanding of plasma processes. The theoretical
frameworkofplasmaphysicscanthenbeintroducedinseveralstepsofrefinement.
In the end, the student (or reader) will see that there is something like the
Schrödinger equation, namely the Vlasov-Maxwell model of plasmas, from which
nearly all phenomena in collisionless plasmas can be derived.
Mysecond credo asexperimentalististhat there isa lackofplasma diagnostics
in many textbooks. We humans have only an indirect experience of plasmas; we
cannottouch,hear,smell,ortasteplasma.Eventhevisualimpressionofaplasmais
onlytheradiationfromembeddedatoms.Therefore,wemustuseindirectevidence
to deduce plasma properties like density, temperature, and motion. Each time my
students have grasped the principle of a plasma process, I ask what we can learn
about the plasma by studying this process.
In preparing this book, I have been supported by many colleagues. My special
thanks go to John Goree, Thomas Klinger, and André Melzer for many fruitful
discussionswhichledtotheconceptofthisbookandforcriticallyreadingselected
chapters. Holger Kersten commented on Chap. 11 and permitted photographing
ix
x PrefacetotheFirstEdition
some of his gas discharges. Many examples in this book were taken from papers
published together with my PhD students and postdocs, which I gratefully
acknowledge (in alphabetical order): Günther Adler, Oliver Arp, Dietmar Block,
Rainer Flohr, Franko Greiner, Knut Hansen, Axel Homann, Markus Klindworth,
Gerd Oelerich-Hill, Markus Hirt, Iris Pilch, Volker Rohde, Christian Steigies,
Thomas Trottenberg, and Ciprian Zafiu. Special thanks go to John Goree and
VladimirNosenkoforthefruitfulcooperationatTheUniversityofIowaduringmy
sabbatical leaves in 2001 and 2005. Many recent results were obtained from col-
laborations within the Transregional Collaborative Research Centre TR-24
Fundamentals of Complex Plasmas. My special thanks go to Michael Bonitz and
his group.
Several colleagues made their original data available: I thank Tom Woods and
Rodney Viereck for their efforts in providing the WHI Solar Irradiance Reference
Spectrum, and Stephan Bosch who made his fit functions for the fusion cross
sections and fusion rates accessible. Horst Wobig provided historic data from the
stellarators WIIa and W7-AS. Matthias Born informed me about the mercury
problem in high-pressure lamps. Permission to reproduce figures was given by
André Bouchoule, John R. Brophy, David Criswell, Fabrice Doveil, John Goree,
Greg Hebner, Noah Hershkowitz, Rolf Jaenicke, John Lindl, Jo Lister, Salvatore
Mancuso,RichardMarsden,BobMerlino,GregorMorfill,JefOngena,andSteven
Spangler. Our librarian, Frank Hohmann, was indispensible in retrieving rare
literature.
The following institutions gave permission to use information from their Web
sites: NASA Hubble Heritage Team, NASA/JPL-Caltech, NASA/SOHO, NASA/
TRACE,EFDA-JET,ITEROrganization,andNIF/LLNL.IPP/MPGkindlygranted
permissions to use figures of the Wendelstein 7-A and 7-X stellarators.
Kiel, Germany Alexander Piel
Contents
1 Introduction... .... .... ..... .... .... .... .... .... ..... .... 1
1.1 The Roots of Plasma Physics.. .... .... .... .... ..... .... 2
1.2 The Plasma Environment of Our Earth... .... .... ..... .... 4
1.2.1 The Energy Source of Stars. .... .... .... ..... .... 4
1.2.2 The Active Sun.. .... .... .... .... .... ..... .... 5
1.2.3 The Solar Wind.. .... .... .... .... .... ..... .... 7
1.2.4 Earth’s Magnetosphere and Ionosphere.... ..... .... 8
1.3 Gas Discharges.... ..... .... .... .... .... .... ..... .... 12
1.3.1 Lighting... ..... .... .... .... .... .... ..... .... 13
1.3.2 Plasma Displays . .... .... .... .... .... ..... .... 15
1.4 Dusty Plasmas .... ..... .... .... .... .... .... ..... .... 16
1.5 Controlled Nuclear Fusion .... .... .... .... .... ..... .... 17
1.5.1 A Particle Accelerator Makes No Fusion Reactor. .... 19
1.5.2 Magnetic Confinement in Tokamaks.. .... ..... .... 20
1.5.3 Experiments with D–T Mixtures. .... .... ..... .... 21
1.5.4 The International Thermonuclear Experimental
Reactor ... ..... .... .... .... .... .... ..... .... 21
1.5.5 Stellarators. ..... .... .... .... .... .... ..... .... 23
1.5.6 Inertial Confinement Fusion .... .... .... ..... .... 24
1.6 Challenges of Plasma Physics.. .... .... .... .... ..... .... 26
1.7 Outline of the Book ..... .... .... .... .... .... ..... .... 27
2 Definition of the Plasma State . .... .... .... .... .... ..... .... 29
2.1 States of Matter ... ..... .... .... .... .... .... ..... .... 29
2.1.1 The Boltzmann Distribution .... .... .... ..... .... 31
2.1.2 The Saha Equation ... .... .... .... .... ..... .... 32
2.1.3 The Coupling Parameter ... .... .... .... ..... .... 34
2.2 Collective Behavior of a Plasma.... .... .... .... ..... .... 35
2.2.1 Debye Shielding . .... .... .... .... .... ..... .... 35
2.2.2 Quasineutrality... .... .... .... .... .... ..... .... 40
xi