The Interaction of High-Power Lasers with Plasmas

320 Pages·2002·3.478 MB·\320

by  Shalom Eliezer (Author)

The Interaction of High-Power Lasers with Plasmas
Series in Plasma Physics
Series Editors:
Steve Cowley,Imperial College, UK
Peter Stott, CEA Cadarache, France
Hans Wilhelmsson,Chalmers University ofTechnology, Sweden
Otherbooks intheseries
Introduction toDustyPlasma Physics
PK Shukla and A AMamum
The Theory ofPhoton Acceleration
J T Mendonc¸a
LaserAided Diagnostics ofPlasmasand Gases
K Muraokaand MMaeda
Reaction-Diffusion Problems inthePhysics ofHot Plasmas
H Wilhelmsson and E Lazzaro
The Plasma Boundary ofMagnetic Fusion Devices
PC Stangeby
Non-Linear Instabilities inPlasmas and Hydrodynamics
S S Moiseev, VNOraevsky and VG Pungin
Collective Modesin Inhomogeneous Plasmas
J Weiland
Transport and Structural Formation inPlasmas
K Itoh, S-I Itohand AFukuyama
Tokamak Plasmas: AComplex PhysicalSystem
B B Kadomstev
Forthcoming titles inthe series
MicroscopicDynamics of Plasmas and Chaos
Y Elskens and DEscande
Nonlinear Plasma Physics
PK Shukla
Series in Plasma Physics
The Interaction of High-Power Lasers
with Plasmas
Shalom Eliezer
Plasma Physics Department, Soreq N.R.C.,
Yavne, Israel
and
Institute of Nuclear Fusion,
Madrid Polytechnic University, Madrid, Spain
Institute of Physics Publishing
Bristol and Philadelphia
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2002 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Version Date: 20150312
International Standard Book Number-13: 978-1-4200-3338-0 (eBook - PDF)
This book contains information obtained from authentic and highly regarded sources. Reasonable
efforts have been made to publish reliable data and information, but the author and publisher cannot
assume responsibility for the validity of all materials or the consequences of their use. The authors and
publishers have attempted to trace the copyright holders of all material reproduced in this publication
and apologize to copyright holders if permission to publish in this form has not been obtained. If any
copyright material has not been acknowledged please write and let us know so we may rectify in any
future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced,
transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or
hereafter invented, including photocopying, microfilming, and recording, or in any information stor-
age or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copy-
right.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222
Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that pro-
vides licenses and registration for a variety of users. For organizations that have been granted a photo-
copy license by the CCC, a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are
used only for identification and explanation without intent to infringe.
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
Preface
This book covers the physics of high-power laser interaction with plasmas,
a subject related to both fundamental physics and the applied sciences.
The book covers high-power laser irradiation, from low-laser intensity
I (cid:1)109W/cm2 up to extremely high intensities I (cid:1)1020W/cm2, and for
L L
laser pulse duration between (cid:1) (cid:1)10 nanoseconds to as short as (cid:1) (cid:1)10
L L
femtoseconds. The plasma medium varies from low densities (dilute gases)
toveryhighdensities(highly-compressedsolidstate).Therelevanttempera-
turescanchangeovermanyordersofmagnitude,andelectricandmagnetic
fields can reach enormously high values.
The interaction of high-power lasers with matter should be of interest
to people from different branches of science who may be unfamiliar with
plasma science. Therefore, the relevant basic plasma physics is developed
and explained in detail. Three basic approaches to plasma physics are
considered, namely the two fluids model, the Boltzmann–Vlasov equations
and theparticle simulation method.
This book is not a summary of research results, but rather it is a
pedagogical presentation where the basic physics issues are addressed and
simple models are used wherever appropriate. The material covered could
serve as a good foundation on which the undergraduate as well as the
graduatestudentcanbuildanunderstandingofthepastandpresentresearch
in this field. For the experienced researcher, I hope that this book is a
comprehensiveand useful presentation of laser–plasma interaction.
The book describes the laser absorption and propagation by a plasma
medium,theelectrontransportphenomenonandtheanalysisoftherelevant
plasma waves. The physics of the electric and magnetic fields in a laser-
induced plasma medium is comprehensively described. The subjects of
laser-induced shock waves, rarefaction waves, heat waves and the related
hydrodynamic instabilities (Rayleigh–Taylor, Richtmyer–Meshkov and
Kelvin–Helmholtz)aredevelopedanddiscussed.Theveryimportantsubject
ofapplications was purposely omitted asit meritsa volume ofits own.
v
vi Preface
Aprerequisiteinplasmaphysicsistoknowandmasterbothsystemsof
units:them.k.s.,knownastheSI(InternationalSystem)units,andthec.g.s.–
Gaussianunits.Furthermore,oneofthemostusefulphysicalquantitiesisthe
laserintensity(energyflux)I ,whichisusuallygiveninmixedunits(Watts/
L
cm2). Although most of the time the c.g.s.–Gaussian units arechosen, both
systemsofunitsareused,inadditiontothepracticalunitssuchaselectron-
volt (eV) for energy ortemperature.
Iwouldliketothankmycolleaguesfromtheplasmaphysicsdepartment
at Soreq in Yavne, Israel, and from the Institute of Nuclear Fusion at the
Polytechnic University in Madrid, Spain, for the fruitful discussions which
were very inspiring, stimulating and useful. I am grateful to D. Fisher for
his critical reading of the manuscript and to Y. Paiss for the valuable
discussions regarding the first chapter of this book. I greatly acknowledge
the help from A. Borowitz, E. Dekel and M. Fraenkel for their help with
the technical problems in preparing the manuscript. My thanks are also
extended to R. Naem for the preparation of the figures. Last, but not
least, my deep appreciation to my wife Yaffa for her encouragement to
write thebook and to bear withme to its successful completion.
Contents
1 High Power Lasers, from Nanoseconds toFemtoseconds 1
1.1 Basics 2
1.2 AStrollthrough a GlassLaser System 7
1.2.1 The oscillator 8
1.2.2 The amplifiers 9
1.2.3 Spatialfilters 10
1.2.4 Isolators 10
1.2.5 Diagnostics 10
1.3 Highlightsof the Femtosecond Laser 11
2 Introduction toPlasma Physics for Electrons and Ions 14
2.1 Ionization 14
2.2 Cross Section,MeanFreePathand Collision Frequency 17
2.3 Transport Coefficients 22
2.3.1 Electrical conductivity 22
2.3.2 Thermal conductivity 23
2.3.3 Diffusion 24
2.3.4 Viscosity 26
2.4 Radiation Conductivity 27
2.4.1 Bound–bound (bb) transitions 27
2.4.2 Bound–free(bf) transitions 28
2.4.3 Free–free(ff)transitions 28
2.4.4 Energy transport 28
2.5 Debye Length 33
2.6 PlasmaOscillations and Electron Plasma Waves 36
2.7 The DielectricFunction 40
2.8 The Laser-Induced Plasma Medium 42
3 The ThreeApproaches toPlasmaPhysics 47
3.1 Fluid Equations 47
3.1.1 Mass conservation 47
vii
viii Contents
3.1.2 Momentum conservation 48
3.1.3 Energy conservation 49
3.2 Eulerian and Lagrangian Coordinates 51
3.3 ‘Femtosecond’LaserPulses 54
3.4 Boltzmann–Vlasov Equations 55
3.4.1 Liouville’stheorem 55
3.4.2 Vlasov equation 56
3.4.3 Boltzmann equation 57
3.4.4 The moment equations 58
3.5 Particle Simulations 61
4 The PonderomotiveForce 65
4.1 The Landau–Lifshitz Ponderomotive Force 65
4.2 The Single-ParticleApproach toPonderomotive Force in
Plasma 68
4.3 The Effect of Ponderomotive Force on WaveDispersion 69
4.3.1 The electron wave dispersion 69
4.3.2 The ion wave dispersion 71
5 Laser Absorptionand Propagation inPlasma 74
5.1 Collisional Absorption (InverseBremsstrahlung) 74
5.2 The ElectromagneticWave Equationin a PlasmaMedium 79
5.3 Slowly Varying Density—the WKB Approximation 81
5.4 LinearVaryingDensity—the Airy Functions 84
5.5 Obliquely Incident Linearly Polarized Laser 88
5.5.1 s-polarization 90
5.6 p-Polarization:the Resonance Absorption 91
5.7 Femtosecond Laser Pulses 96
6 Waves inLaser-Produced Plasma 105
6.1 Forewordto Parametric Instabilities 105
6.2 The Forced Harmonic Oscillator 110
6.3 Landau Damping 112
6.4 Parametric Decay Instability 115
6.5 StimulatedBrillouin Scattering 120
6.6 A SolitonWave 124
6.6.1 Ahistorical note 124
6.6.2 Whatis asoliton? 126
6.6.3 Whatis asolitary wave? 126
6.6.4 The wave equation 126
6.6.5 Ion plasma wave and theKdV equation 127
7 Laser-Induced Electric Fields inPlasma 134
7.1 High- and Low-FrequencyElectricFields 134
Contents ix
7.2 Expansionof Plasmainto the Vacuum 135
7.3 Double Layers 138
7.4 Charged Particle Acceleration 140
7.4.1 Astaticmodel 140
7.4.2 Adynamic model 141
8 Laser-Induced MagneticFields inPlasma 144
8.1 The rn(cid:2)rT Toroidal Magnetic Field 145
8.2 Magneto-Hydrodynamics and theEvolution of the
MagneticField 146
8.2.1 The generalized Ohm’s law 147
8.2.2 The magneticReynoldsnumber 151
8.2.3 MagneticReynoldsnumbersR (cid:3)1 151
m
8.2.4 MagneticReynoldsnumbersR (cid:4)1 152
m
8.3 Faraday and Inverse Faraday Effects 153
8.3.1 The Faradayeffect 153
8.3.2 The inverse Faraday effect 157
8.3.3 Angularmomentum considerations 159
8.4 Waves inthe Presence of theSteady-State Magnetic Field 162
8.4.1 Ordinaryand Extraordinary Waves 162
8.4.2 Electromagneticwavespropagating parallelto B 165
0
8.4.3 Alfve´n waves 168
8.5 Resonance Absorption in a Magnetized Plasma 169
9 Thermal ConductionandHeat Waves 175
9.1 The Scenario 175
9.2 The Rocket Model 180
9.3 Relaxation Rates 183
9.4 The Fokker–Planck Equation 189
9.5 The Spitzer–Ha¨rmConductivity 195
9.6 Hot Electrons 198
9.7 Heat Waves 205
10 ShockWavesand Rarefaction Waves 213
10.1 APerspective 213
10.2 Sound Waves 216
10.3 Rarefaction Waves 219
10.4 Shock Waves 221
10.5 Shock Wavesin thePresence ofMagnetic Fields 233
10.6 The Study of High-Pressure Physics 237
10.7 Studies of Equationsof State 241
10.8 Studies of DynamicStrength of Materials 249