Physics of high-intensity high-energy particle beam propagation in open air and outer-space plasmas

1.9 MB·English

by  Andre Gsponer

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h The Physics of high-intensity high-energy
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m Particle Beam Propagation
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h Andre Gsponer
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Independent Scientific Research Institute
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3 Oxford, OX4 4YS, England
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1 ISRI-82-04.56 January 11, 2009
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1979 — 2009
“Nuclearphysicshasputintothehandsofmankindformidablepower.
Wearestillstrugglingwiththeproblemof howtousenuclearenergy
efficiently and safely, we are rightly alarmed at the accumulation of
nuclearweaponsofannihilation. Untilmankindhasshownthatitcan
deal wisely with nuclear power, it is not prepared for something en-
tirelynew. Untilthelastnuclearwarheadhaseitherbeendispatched
to outer space or quitely burnt up as fuel in an energy-producing re-
actor,Iwouldnotwelcomeanentirelynewdevelopment. Ihaveoften
said that I am in favor of supporting high energy physics, provided
that the high energy physicists can promise not to produce applica-
ble results within the next twenty-five years. I am usually not taken
seriously when I make such remarks. I do, however, mean them very
seriously.”
H.B.G. Casimir,
The25thAnniversaryCeremony,
CERN Courier,
September1979,
page237.
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Abstract
This report is a self-contained and comprehensive review of the physics of
propagatingpulsesofhigh-intensityhigh-energyparticlebeamsinpre-existingor
self-generated plasmas. Consideration is given to beams of electrons, protons,
muons, and their antiparticles, as well as to neutral-hydrogen, positronium, and
electron-positron-plasmoid beams. The first part is a systematic overview of the
theory pertaining to propagation, plasma self-generation, energy/current-losses,
and stability of such pulses. The second part reviews the major full-scale propa-
gation experiments which have been carried out, in atmospheric and outer-space
plasmas, to assess the validity of theoretical models. It is found that the data
available on these experiments demonstrate that range and stability are in agree-
ment with theory. In particular, stable self-pinched propagation of high-current
charged-particle beams in the atmosphere is possibleoverdistances equal to sev-
eral Nordsieck lengths. In order not to be deflected by Earth’s magnetic field,
electron-beam pulses need to be guided by a pre-formed channel, while proton-
beam pulses may under suitable conditions propagate undeflected through both
the low-and high-atmosphere. In ionosphericorouter-space plasmas, very-long-
range propagation across Earth’s magnetic field requires GeV to TeV electrons
or positron beams in order for the transverse deflection to be acceptable, while
undeflected propagation is possible for plasmoid beams consisting of co-moving
high-energy particlepairssuch as electronsand positrons.
Contents
1 Introduction 8
2 Somepreliminary definitions and concepts 10
3 Particlebeam propagationinvacuum ora negligiblemedium 15
3.1 Neutral beamin vacuum: ballisticpropagation . . . . . . . . . . 15
3.2 Charged beamin vacuum: space-charge-driven expansion . . . . 17
3.3 Injectionofacharged beam intovacuum: limitingcurrent . . . . 20
3.4 Inductivehead erosion . . . . . . . . . . . . . . . . . . . . . . . 22
3.5 Injectionintoouter-space: spacecraft charging . . . . . . . . . . 25
4 Particlebeam propagationina gasorplasma 27
4.1 Beam charge and current neutralization . . . . . . . . . . . . . . 27
4.2 Charged beamin aplasma: theBennett pinch . . . . . . . . . . . 33
4.3 Effect ofinternalforces : cohesionand coupling . . . . . . . . . . 41
4.4 Effect ofexternalforces : Earth’smagneticfield . . . . . . . . . . 46
4.4.1 Effect oncharge andcurrent neutralization . . . . . . . . 48
4.4.2 Effect onbeam trajectory . . . . . . . . . . . . . . . . . . 49
4.4.3 Effect onbeam head . . . . . . . . . . . . . . . . . . . . 51
4.4.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.5 Charged beamin adensegasorplasma: Nordsieckequation . . . 57
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4.6 Particlebeamin agasorplasma: emittance-drivenexpansion . . 64
4.7 Deflection and guidingby conductorsandchannels . . . . . . . . 66
4.7.1 Deflection andguidingbyconductors . . . . . . . . . . . 67
4.7.2 Magnetictrackingin dischargeplasmachannels . . . . . . 70
4.7.3 Electrostatictrackinginion-focusingchannels . . . . . . 71
4.7.4 Electrostaticchannel-trackingin full-densityair . . . . . . 75
4.7.5 Magneticchannel-trackingin full-densityair . . . . . . . 76
5 Injection ofa high-power beam into theatmosphere 78
5.1 Plasmagenerationby aparticlebeam . . . . . . . . . . . . . . . 78
5.1.1 Maxwell’sequationsand beam coordinatesystem . . . . . 80
5.1.2 Circuitequation . . . . . . . . . . . . . . . . . . . . . . . 82
5.1.3 Conductivityequation . . . . . . . . . . . . . . . . . . . 85
5.1.4 Current enhancement . . . . . . . . . . . . . . . . . . . . 87
5.1.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.2 Charge neutralization: limitationsdueto atmosphericdensity . . 89
5.3 Conductivitygenerationand criticalbeam current . . . . . . . . . 94
5.4 Ohmiclossesand return-current heating . . . . . . . . . . . . . . 97
5.5 Beam head erosion . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.6 Beam conditioning . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.7 Propagationofatrainofpulses . . . . . . . . . . . . . . . . . . . 107
6 Stability ofpropagating high-power beams 108
6.1 General considerationsonbeam stability . . . . . . . . . . . . . . 108
6.2 Microinstabilities . . . . . . . . . . . . . . . . . . . . . . . . . . 113
6.2.1 Two-streaminstability . . . . . . . . . . . . . . . . . . . 114
6.2.2 Weibel(ormicro-filamentation)instability . . . . . . . . 116
6.2.3 Beam-plasmaheatingbymicroinstabilities . . . . . . . . 120
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6.2.4 Discussionofmicroinstabilities . . . . . . . . . . . . . . 120
6.3 Macroinstabilities . . . . . . . . . . . . . . . . . . . . . . . . . . 121
6.3.1 Macro-filamentation . . . . . . . . . . . . . . . . . . . . 122
6.3.2 Electrostatickink(or‘ionhose’)instability . . . . . . . . 124
6.3.3 Electromagnetickink(or‘resistivehose’)instability . . . 126
6.3.4 Macrostabilityofabeam penetratinganeutralgas . . . . 128
6.3.5 Macrostabilityofbeamswithrounded radialprofiles . . . 130
6.3.6 Discussionofmacroinstabilities . . . . . . . . . . . . . . 133
6.4 Masteringand dampinginstabilities . . . . . . . . . . . . . . . . 133
7 Plasmoidbeam propagation 135
7.1 Plasmoidsinfundamentaland appliedsciences . . . . . . . . . . 135
7.1.1 Compactplasmoids . . . . . . . . . . . . . . . . . . . . . 138
7.1.2 Beam plasmoids . . . . . . . . . . . . . . . . . . . . . . 141
7.1.3 Time-scalesforbeamplasmoidpropagation . . . . . . . . 143
7.2 Propagationacross amagnetizedvacuum . . . . . . . . . . . . . 144
7.3 Propagationacross amagnetizedplasma . . . . . . . . . . . . . . 150
7.4 Gaussian-profilebeam plasmoidmodel . . . . . . . . . . . . . . . 154
7.5 Feasibilityofmatter-antimatterbeam plasmoids . . . . . . . . . . 161
8 Scientific and technical prospect 166
8.1 Discussionoftheoreticalprospect . . . . . . . . . . . . . . . . . 166
8.2 Discussionofbeam propagationexperiments . . . . . . . . . . . 169
9 Neutral particle beams propagationexperiments 172
9.1 Neutral hydrogenbeam technologydevelopment . . . . . . . . . 172
9.1.1 Theionsource . . . . . . . . . . . . . . . . . . . . . . . 173
9.1.2 Theinjector . . . . . . . . . . . . . . . . . . . . . . . . . 173
9.1.3 Theaccelerator . . . . . . . . . . . . . . . . . . . . . . . 174
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9.1.4 Thebeamfocusingand steeringoptics . . . . . . . . . . . 175
9.1.5 Theneutralizingcell . . . . . . . . . . . . . . . . . . . . 175
9.1.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 176
9.2 BEAR andGTA at LosAlamosNationalLaboratory . . . . . . . 176
9.3 Emergingneutral beamtechnologies . . . . . . . . . . . . . . . . 179
9.3.1 Antihydrogenbeams . . . . . . . . . . . . . . . . . . . . 180
9.3.2 Positroniumbeams . . . . . . . . . . . . . . . . . . . . . 181
9.3.3 Ultra-high-energylaserbeams . . . . . . . . . . . . . . . 181
9.3.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 181
10 Charged particlebeams propagationexperiments 183
10.1 ATAat LawrenceLivermoreNationalLaboratory . . . . . . . . . 183
10.2 RADLACat SandiaNationalLaboratory . . . . . . . . . . . . . . 189
10.3 LIA-10 andLIA-30 at Arzamas-16 . . . . . . . . . . . . . . . . . 193
10.4 PHERMEX at LosAlamosNationalLaboratory . . . . . . . . . . 194
10.5 Otherelectron-beampropagationexperimentsin theUSA . . . . . 195
10.5.1 DARHT —2 kA, 3.5MV,2 µs . . . . . . . . . . . . . . 195
10.5.2 HermesIII —19 MeV, 700kA, 25ns . . . . . . . . . . . 196
10.5.3 IBEX — 70kA, 4Mev,20ns . . . . . . . . . . . . . . . 196
10.5.4 MEDEAII— 13kA, 1.2MV, 2 10ns . . . . . . . . . 197
×
10.5.5 Pulserad 310— 5–10kA,1 MeV, 35ns . . . . . . . . . . 198
10.5.6 Febetron 706— 5kA, 0.4MeV, 3 ns . . . . . . . . . . . 198
10.5.7 Stanford MarkIII —10 A, 42MeV, 4 ps . . . . . . . . . 199
10.6 Propagationexperimentsin othercountries . . . . . . . . . . . . 200
10.7 High-intensityproton andion beams . . . . . . . . . . . . . . . . 201
10.7.1 Accumulationand pulsecompression . . . . . . . . . . . 202
10.7.2 Collectiveacceleration . . . . . . . . . . . . . . . . . . . 203
10.7.3 Diode-likesources . . . . . . . . . . . . . . . . . . . . . 203
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10.7.4 High-intensityprotonbeam propagationexperiments . . . 205
10.8 High-intensitymuonbeams . . . . . . . . . . . . . . . . . . . . . 206
10.9 Ultra-high-energyparticlebeams . . . . . . . . . . . . . . . . . . 208
11 Conclusion 210
12 Aboutthis report 211
13 References 221
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List of Figures
4.1 Thepincheffect . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.2 Beam expansionforvariousparticles . . . . . . . . . . . . . . . . 59
4.3 Effectivebeamrangeversusmomentumforvariousparticles . . . 60
5.1 Propagationofapinchedbeam . . . . . . . . . . . . . . . . . . . 79
5.2 Coordinatesystemused indescribingthepropagatingbeam . . . . 81
5.3 Beam neck profile . . . . . . . . . . . . . . . . . . . . . . . . . . 101
8.1 ‘Dream Beam:’ Ultra-high-energy laser-drivenbeam . . . . . . . 170
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List of Tables
4.1 Typicalionosphericand magnetosphericdata . . . . . . . . . . . 29
4.2 Behaviorofa3 MeV, 50kA, 30ns electronbeam in air . . . . . . 40
4.3 Rangeofa10 GeV/cplasmoidbeam propagatingin outer-space . 66
5.1 Atmosphericdensitylimitationson beam current density . . . . . 90
5.2 Atmosphericdensitylimitationson charge neutralization . . . . . 92
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