`ecfited by
`Lean J. Raciznemskl
`
`Las Cruces New Meme:
`
`>
`REV! 6:. R Creme:
`ChemiCai and £338" Screams Division
`L03 Mamas Natmnai Labaratory
`L03 Atamos New Maxim
`
`
`
`
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`
`
`MARCEL DEKKER, INC.
`
`New York and Base!
`
`ASML 1017
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`ASML 1017
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`

`

`
`
`
`
`Library of Congress 611111111631ng:i114PnbtisatiQn. Dam- ,,
`Lasemnduceci 11131111118. 911"" "11%;; 11113111112111 111111 11111112311111 fippficationsf editeé
`
`
`1‘1
`3.131125111131133, "
`
`
`V
`.
`_
`11:33.11 131111111.)
`
`ISBN 832
`
`,;:';j“_gt111011131113611 1.. Radzi’ems'ki, Leon 1.,
`1 P1131111: a:
`
`‘ $9173.83
`1311*
`
`.
`
`
`
`This 11131131: is 1111111111111 1311 1111111111161 291111111.
`
`Copyright 113 1989: 11111112311331411311 1111:.
`
`2111 1111111 Reserved
`
`Nei1her this 1111113: 1111: any part may b3 repmduaed 111 transmitted in any {111111
`1:11 by 1111}; 111eans,eeiec1mnic :11 mechanicai including phetucopying, microfilming,
`and recommg, or by my ,1111‘011111111011 sterage and retrieval system: without per
`mission 1111111111151, from the pubiisher.
`
`MARCEL DEKKBR INCL
`270.Madison 11173111111, N611! York, New York 10016
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`Current printing (last ctigit'):
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`PRINTED IN THE UNITED STATES OF AMERICA
`
`
`
`

`

`Contents
`
`
`
`ster-Indxlc:efl.,’Breakfiown: An U’gxdam
`
`ayl
`
`
`
`
`
`Igtgaductian
`Caatmn afinmai Hicctrons
`,
`Eieman {Emmi} in Gases
`Lasép’ljnfiumd;Eradicflmm 0f, Balms anti {Lingias
`.. (inmiudiag Rgmarks
`,Rafmences
`
`
`
`fiddling.bfiwsifiraakaawn Phenomena
`wharf G Ram
`
`i’iitfafiaciibn
`{1315553525811 0f a ’Pmpagating E’iasma
`Absmptign Chafanteristits {3f Heatsfi Gases
`Fat-11:55.33? fiagagazing Plasmas
`
`
`
`Caitwflimeasianal Laserfiuppm‘ted Batonatian Wave
`OneJBimansimai Laserfiuppfirted Radiating Wave
`'fiansiéfia‘n Reg-ism
`Radial Exgansian
`8 Thgztmal Cgupiing
`3:313. Otherfiactom
`212 Summary
`References
`
`»
`
`
`
`3 lintmductiun to Laser 'Piasma. Diagnostics
`,,
`,» Allan A. Heme: and Hector A. Baldis
`
`34.1
`3.2
`
`Introduction
`
`Introduction to Optical Diagnostics
`
`ix
`
`iii
`3;"
`
`36
`
`59
`
`6.29
`
`6‘9
`
`'38
`
`72
`
`7,5
`7’?
`
`88
`
`9'2
`
`93
`
`:95
`
`99
`
`100
`
`101
`
`1-01
`
`105 ‘
`
`105
`
`110
`
`

`

`
`
`
`
`x
`
`3
`
`Cantenis
`
`3.3
`
`Intmduatéon to X—ray Diagnostics
`
`References
`
`4 Lgse'nsvtxstaineti Pias’mas
`Dennis R. Keefer
`
`‘
`
`Intmducticn
`4.1
`Princigfics cf Qperzifian
`4.2
`Afifii’yfical Medals
`43
`Experimental Studies
`4.4
`4.5 Applieatimzs (if the LasapSustaixzed P15511121»
`Refemnces
`v
`,.
`
`‘
`
`.
`
`5
`
`{martian}! Confined. Fa’simt
`Robert L. Mchry a115,}aha; M 'Saures
`
`5.1
`5.2
`53
`5%:
`5.5
`55
`5.5?
`5.8
`
`v
`
`,
`
`IfiiS‘th‘iflfli Overview
`Laserfi'Fusion Snafing Laws
`Coronal ’Phygics
`X421}: Gena-rating by Laser~Fmdmed Plasmas
`LasabDriven 151333551;
`flyidmfiynamic Stab’fiity 9f:Abiéi’iiv’ély Di‘ifiifin; 3116113
`1535.55.92: Unifmmigy quuimmama
`Impiosifin Experiments
`Rflffii‘fifiéfis
`
`'
`
`6 LaseruBased :Semimnfimmr5535555552:
`
`Jaseph R. ’Wachie‘r
`
`15.1 Aspects 0f Semiconducter Fabrication
`5.2 Applications 0f Lasers iii-tilt“: Semiconductor Indusztry‘
`6.3
`Research Areas '
`i
`5
`6.4 Outlook
`Refarencas
`
`'
`
`7 ; S-pectmchemical Anaiysis Using Lager i’lasma Excitatiun
`Leon J. Radziamski and David A. Cremers’
`
`Review
`7.1
`-Methods. and Properties of Analysis Using Lassr I’iasmas
`7.2
`Analysis of Gases,
`73
`7.4 Analysis of Bulk Liquids
`7.5 Analysis ofParticlas
`7.6
`Analysis‘of Solids
`7.7 Advances in Instrumentation
`
`
`
`-
`
`5
`
`131.
`161.
`
`169
`
`169
`1'22
`1182
`189
`1'95
`293
`
`287
`
`20‘?
`2.11
`217'
`22-4
`227
`239
`.243
`251
`250
`
`269
`
`269
`276
`233-
`290
`2’91
`
`295
`
`295
`296
`302
`306
`309
`313
`318
`
`

`

`fiifi‘flifi
`
`
`
`ngnasi’s
`Raferences
`
`
`
`{mg W. Kim
`
`
`unfla‘meniais of fifia’ly‘sis of Semis by'Las-exsi’t‘oduced
`
`Mamas
`
`
`
`
`Gimme-r Organization
`I’mmfiuativn
`’I’ihemmanalagy {Oi Laser Heating of Candensed~Phase
`
`
`Targets.
`
`'téivafipec’triésmgy
`Quanta:
`
`‘Ifltefifii y Mcasmaments and. Elemental Analysis
`‘ Summary
`
`References
`
`Laser Vapm‘izafifln far Sample Introduetian in Nomi-(1:311:61
`sass giwctx‘fififiapy
`asap}: Sue-damn, “Rem: G. Mitchell, and NicholasS Hagar
`
`
`,fimnvcnfiimai Shim Sampifi ’Intr-oéiuctiun it» Atomic
`Spesimscapy
`Laser. Afiiafifin af’Sefid 33211333223
`Laser Ablatinn far. Sampk; Intriafinctica in. Atomic
`S-pectmampy
`Raiafim Merits {3f Lag-at Ablatian for Sam’pic ’I‘mmductim
`in Atn'mic S’pec’tmseopy
`-
`Lassa!“ Samms fur Mass Spectrumeiry
`Applicatians of Laser ’Micmpmbc
`Appliemions 0f Laser Desorption and Postionization
`:Conclusiain
`
`References
`
`
`
`
`
`Current New Appiications of Laser Plasmas
`Allan A. Bauer, David W. Forsiund, Colin J. MCKinstrie,
`Justin S; Wark, Philip J. Hargis, Jr., Roy A. Hamil, and Joseph
`M. Kindel
`
`10.1
`
`Introduction.
`
`10.2 Applications of Lassr~Plasma~Generated anys and
`Particles
`10.3 Laser~Plésma Acceleration of Particles
`
`xi
`
`321
`
`32.3
`
`32?
`
`32.7
`
`327
`
`330
`
`33,5
`
`341
`
`344
`
`345
`
`347
`
`34'?
`
`35!}
`
`353
`
`363
`
`365
`
`369
`
`372 _
`376
`
`376
`
`385
`
`385
`
`386
`
`413
`
`

`

`xii
`
`.
`
`’
`
`.
`
`Contents
`
`1&4 Lasars—Puisnd Paws: Switching
`Refierences
`
`1:1ng
`
`-
`
`f
`
`424
`432
`
`43:7
`
`
`
`

`

`
`
`
`ngoruSusi-aiood Piasmaa
`
`Semis 811139131
`
`Center for LaserKypfwoaaas
`{1511;121:1511}? of11111111333116 Spams 1213111316
`31111111191111 finaessee
`
`4.1 ZNTROBHCTION
`
`'
`
`1
`
`‘
`
`Plasmas Creatod by the 11111111111111-1111111111111111111111111.1111 11111111112111.1161?»
`»
`.
`1
`’.
`’
`’
`.'
`.
`-
`1111:1611, rubyiasers 11111111111161
`111. 111(1963) Those 13111111111113 for
`"““121111113? :11 gas breakdown 111;
`111-1»: focus of. a 16118 and 1161113111 1
`
`’
`
`a p1asma111 a staadrstata 1111111111101111»111‘ 111.11 focus of .111311111” 11111111, 111111 1111:
`first 11131111111111; (11116111311911 of a “connnuoasoptical d1$c11a1go was 11%
`ported by Genoraiov at 111. {$711) T1113 continuous, ham—sustained 11111311111
`(LS?)111 often referred 10 as a contmuous optical 111113113131: (£20113) and 11
`has a numbox‘ of unique propartios that 11111111311 1111 interesiiog candidate for
`a varioty of apphcations.
`The laser-3113111111311 plasma shares many 12111111616111.1103 with 011161 gas
`discharges, as explainedto detail by Raizor (198(1).111 his oomprohonsiva re~
`vi,ow but it is sustained through absorption of power from an optical beam
`by the pr'ooossofmvorse bromsstrahlung.31nco the optical frequency of the
`sustaining boam is greater than the plasma-frequency, the beam is capablo of
`propagating well into the intorior 0111111. plasmawhore. it is absorbed at high
`intensity near the focus: This is in contrast to plasmas sustained by high»
`frequency electrical fields (microwave and o'loctrodoloss discharges) that
`operate at frequencies below the. plasma frequency and sustain the plasma
`through absorption within a thin layer near tho'plasma surface, This funda-
`mental difference in the power absorption mechanism makes it possible to
`
`"i 69
`
`

`

`170
`
`,
`
`Keefer
`
`generate eteadystatepiasmas havmg maximnm temperatures bf .10{30011201
`11111111111 1131111111 veieme near 1111110131111 {11111111111211 Way from any cenfimng
`3111111111111. A 1111010 01‘:111111111121.sestnmed 1:13:21 1215611 beam focusedwith a lens
`
`is 511011111 111 Fig 41;:
`.
`1,
`laser was 10
`.
`" by a. 1’
`111
`feta} 1engt11 161115 into 2 111m bf Sewing 111»
`gen. Pg 4. ( ,)shews schemancaily 1191111113 11111811121 farms within the {£31311
`regien.
`
`1- the LS? canbe operated snceehe
`"barges that operatein a fiewmg
`.
`envxenment have been caiied “pIaamatrens”111 the Soviet iiterature, and
`the laser-3113:1111ed 111.11:12:. is oft-e11 referred 10 as an. “optical phsmatmn.’
`
`
`
`
`
`
`111113; £131" "£1113 lasebsustamed pIaSma' Sinee the LS}? can.
`_
`.
`.
`roger: and the gamer can be beamed remerely, it 1121:»:
`,,
`epemte111 per
`been pxepesed that the LS? 11011111 be used fer h1gh specifieimpulse space
`11111911111011 Anumher 01 papers have-11113111111111 this. application, and it was
`the subject. of a renew by (1111111113 and Krier (1984) Thompson et a1 (1918)
`described exnerxments 1111 which 121361“ energy was converted 11110 eieetrieai'
`energy 115ng a laseesusitained argon 111211111121. Cremers e: 211. (1985) have
`suggested the L8}? as a source in: sp-eetmchemmai111111131513 and given some
`experimental results. Cress and Cremers {1986) have sustained plasmas1n
`the threat of 21 51115111 11022115: 111 produce atemic oxygen having a direeted
`vefocity of several kmlsee for the laboratory study of surface interactions at
`energies and particle fluxes similar to these experienced by satellitesInlow
`earth brbit. Other applications are suggested by analogy to other plasma
`devices including light seurces, piasma‘ chemistry, and materials processing
`The physical procesSes that determine the unique characteristics of the
`LSP will be discussed111 Sec 42, and the theoretical analyses that have been
`used to describe the LSP will be addressed111 Sec. 4 3.Expe1.imental 16311113
`obtained will be presented in Sec. 4.4 and compared with the theoretical
`predictions. Sec. 4.5 will consider some possible applications.
`
`.
`
`

`

`Laser‘suszame-a fiasmas
`
`‘
`
`1 Ti
`
`
`
`(b)
`
`(a) Photagréph of a plasma sustained by: a 600 W carbon dioxide laser?
`Figure 4.1
`bgam focused Mill 3 191mm fiscal length lens. (b) Schematic representatian ShOW~
`ing how the plasma forms within. the focal V'oiume.
`'
`
`

`

`“172
`
`Keefer
`
`4.2 FMNCIPLES 033‘ OffilRATHBN
`
`Plasmas that are creaied pr 5113131116111 113.! Erasers can, be generatedm a variety
`
`
`try usefi ta gensrata the;
`' zghfinmig}!131313136 188318 can gancram plasma
`bmakdawn {11:61:11}! 12111111111 21 gas {hat{1331:1113 in :3 transient fixgancfing 111333118
`5imi1arto an expmmon. A1; 14.31%: iasm‘ intensifies am} longs: puke {137165,
`
`
`
`
`
`, aims ccmbnstmn {1130)wave.
`Thesc: transxent plasmas have bear: {5118611336131 by Banter {1988) 211161 1111111101:
`
`51‘ 31:14:11 £113 apnea}
`
`
`
`coniaining boundamcs. A fundamemal dgfiamnce2m the way in which en—
`-ergy is absorbeé by 121691353113 is wwemifilé £01: $116313 unique» charactfiristics
`of the: LSP.
`.
`
`4.2.1 Easic Physica'i Pracesses
`
`In a dimctt current (dc) arc or in an infiuctively cougfiad plasma (RE), en-
`ergy is absm‘bed through ohmic heating predated by. the loW~fmquency or
`direct currants flowing in the plasma. The elm'trical canductivity of an ideal
`plasma 1‘sgiven by (Shka’mfsky at 211., 19613)
`
`2
`
`m,
`
`
`Wig—(V W)
`
`I
`
`(411)
`
`breakdmwnm tha gas, hmvgverg and anauxiliary saurce must be used to ini-
`tiate theplasma. A sketch-11f a steadystateIaser~5ustained plasma is shown
`in Fig 41(1)) The plasmamay 13% smiamed mthm a (131111;;ng chamber :0
`60111101 the flow and pmssure {31‘ 111-01331} air 03': a Imge chamber where the
`flaw:3 determined by {karma} buoyancy
`In many Ways, £111: laser-sustained 131513111318 3113311111” ta direct current or
`imwfraqumay eiactmsielm'22ch1:111:11. mmmwavg diachargfis that am Caper-
`
`the currents are transmitted through the plasma bstween clectrodes and
`
`m 222 ~1~ w?
`
`wheren is tht: Electron density, 8 thr: electronic charge, m the electron mass,
`co the radian frequency of tbs applied electric field, 1/ the efiéctive collision
`frequency for electrons, andi thesquarc mot 0f ml. In the dc arc (w a 0),
`
`

`

`
`
`Lasertfiumamed Plasmas
`
`'
`
`-.
`
`A 173
`
`the size of the plasma is notormined by the size and spacing of the electrode.
`and the confining boundaries.
`In the 10111116 currents are: inducsd into
`the plasma from alternating Commit flowing in a surrounding 3016110112131
`
`(2.011.. The are is sage
`111613 within a Container that determines the plafima
`diameter, whereas the Inn 131} of the plasma is determined by the length of
`the adenoid,
`‘1
`3.116%? operates at. frognenoies WEE below the {31.351113 frequent}?
`
`=2
`
`1162"» 112
`(1 .
`--'—-«
`
`’
`
`.
`
`>
`1 >
`'11.,2'
`
`whom :39 ittho permittmty of fine space In this frequent}: range, the 616-1134
`tromagnatm flair} tines not propagate as a. wave within 1116 plasma, butis
`attenuated asan: nvannsnnntwave (Holt and Hask-311,1965) over distances
`of the order ofthe skin depth '
`
`
`
`(43}
`
`when.» c: is the- speeii of night; Thus, thapmsma is 31151311166 by 61161331613,“
`sorbeti within 21.811121111813113? near its outer 5111111166 that pronouns a rathnrflat
`tnmperatnrn promo w‘ 111:; the. plotting 2111611111113 the. maximum {Endpoin-
`
`tnms that can fife obtained
`The frequency 6111116apnea; fiettis (28 THz for the it}6 pm carbon diox»
`166121361) usedfor the; LS1?is greater than the plasma frequency, and there-
`fore? {1161116168111 laser beam nan propagate -we11 into the intarior b31616
`it is signifioanfiy abs-01136661113631; the process of ,inyarse bremsstrahlung
`(Sixkarofsky at 211., 1966} Since tin: focusing of the laser beam producsd
`by a 16115 01* mirror is essentiaily preservnd as the: beam propagates into the
`plasma, very largefieiii strengths may be produced within the plasma near
`the beam {01133.1115 these; large field strengths that lead- to peak. tmnpera.w
`turns in the: LSP that are gnnnrafly greater than those obtained with eithsr
`dc arcs or the EC? and make it possible to sustain a small Volume of plasma
`near the focus, well away from any confining walls.
`Inverse brnmssttahiung is a process in, which the plasma electrons ab~
`sorts photous from the laser beam during inelastic collisions with ions, new
`11,313, and othor emotions. The Collisions betwaen electrons and ions are”
`the dominant, process for the LSP and the absorption Coefficient is given by
`(Shkarofsky et 31., 1966)
`
`
`w ire 311.506
`1~e"”“’”‘T
`(w)
`171‘
`hw/kT >
`
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`
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`
`'
`(4‘4)
`
`
`
`

`

`176
`
`’
`
`, Keefer
`
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`1166 .
`11611.1611g111 L11616 6 11611111111111,1611g1h 66616 £61£116 LS . 11166 11 {16161:
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`3611,11516 11111161151611 £11 1116 111gh~16mp61611116 111161116111!
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`11161111111 66111111611611 and 1611161116 166.6 16661161116166
`T116 3166111011 61“ 1116 LS? 16161116 to 1116 £6661 paint is 61111621116 1161161111116
`111g116 6111161616 and1116 range 61 11211611161616 1‘61: which. it 61111 1.1611161111611166
`thm 1116 plasma. is 111111611611 11661 1116 13.6.3111 £06116, it pffitpagatafi 111161116
`sustaining beam and seeks 6 61211116 position. The 1366111011 68161111113; will be
`located “111616 the. 116361 intensity is just 611111616111 1661.11166116611166 power
`will baiance theless‘es due to convectian, thermal 66111111611611, 61161116111161
`radiation. A number of factors 60111131116 to (161611111116 this 1366111611 of sta-
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`and. aberrations of the facusing 1611s or mirwr’, 1116 plasma 6166511116, and the
`incident flow vsiocity (Keefer 61; 61., 1986; Walla et 61., 1987).
`The power per unit volume that is absorbed'by the 131216111616 given by
`
`P7 :2: a]
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`
`
`3’15
`
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`11311311111111» profile of 11112111016311: 131111111 as "1171131 115131111 focal '3ong131 and abor~
`rations of the lens, 1111:1313 characteristics 11111 11111111111011 11111111111191: within
`the focal region at 1133111111 thoamzmmum 1111131111113 intonsity 11111121111311 For
`611311133313, 11311151111111 11111111113113 ' "11$, 11161111611311}: 1311311331311 11113111131 withup
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`For a 1argerffnumber system, 11113311181153)? 1131312111165 1633 rap-31133,: and the»
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`plasma win 11111311126 11?:11:13031111111 £112»
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`buoyancy induces a flow 11311531113610 11131113111231 111.13. Tho 3111311111113 flow
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`Iish an uppe: power 1111111 when 11111 13113311111311: Was operatod with tho beam '
`propagating vertically upward. Koziov 61.111 (1974) deyoioped a radmtivo
`model for the 1.31" and oxplainod the nope: power limit on the basis that
`the plasma must stabfilizo Close enough to-tho focal point. that the geomet~
`' ric increase of laser 33611111 intensity» going. into 1hoplasma W115 greater than
`the loss of intensity due to absorpfi-on. The}; speculated that the faii‘ure of
`Generaiov at 3'1. (1972) to observe this limit :in a vertical beam was (1116 to
`rapid extinction and reignition of the plasma.
`It. is clear from the experiments 13163116131011 at al. (1972) that flow Can
`have a large effect on the range of 13113531116 and lasor power that will support
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`port 1133135 313331131: to 31333333331 1:933:33an but may be significanfly larger
`Detailed 6.331011133110133 of the 131’ (long and Keefer, 1986) indicate that this
`radiative transport is a dominant factor111 the determination of the struc—
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`(16363313111335 the temperature gradientm tho upstraam 110331 of the 13121331323,
`thereby determining the position in tho beam for which c0nVection losses
`are ba1anccd byabsorption
`The position of stability fan the LSP also dopends on tho plasma pxes~
`sure The. absorptiou coefficientis a 31:1ng function of plasma density, as '
`seen from Eq ..(44). If the pressure is incroasocl and the 313303ption oooffi
`cient increases, than the plasma can absorb more power from the beam and
`will move away from the focus to a lower intensity region in the boam. At the
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`60111211116113, 661161ng a wider range of 13016111161 66111106116115
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`11.2.2
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`31111511111 Characteréstics
`
`LaSSPSuStaiflBd plasmas have been operated in 21 1121116131 of molecular and
`rare gases at 13163511165 from 1 to more than 200 61111. The resulting plasmas
`have characteristics that are similar to are plasmas operated at similar p163-
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`sures, 1:353 2125 5355.32 2551553525553152335 LS? 5.35 usually somewhat highar
`2.13511 2332255 for 23.25 5232555253315 5325, 33532151155 from 2.125 plasma 5531 be a 535»
`55315552 32552155 cf the 2231531 522332.252 322553, 5:521 3553152155 22555552291535 5-
`major 25.15115 215252522535 "22325 structure 51‘ 2125 plasma, Continuum 5335525—
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`{352551511532 of 23235 radiatimi is straightfmward, 53~
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`2223313311521 when the 5165th collisional 3:525 33120555555 23053321525 the pro-
`cesses Of radiative decay and rccembinafion. When LTE is established
`in 2115 plasma, the density in specific quantum 52525.5 is the. same- as a sys—
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`perature, and chamicalcompesition.
`It 53h0u1d be 5122;33:551sz that this
`(3055 net imply that the radiation is similar ta 5 blackbody at the plasma
`temperature. In general, 1315 spectrum of the radiatien from the plasma
`will have a complex structure. consisting of the superposition of relatively
`narrow Spectral lines and 5 continuum having a complex. spsctral struc-
`ture.
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`In Figs. 4.2- 4I, 11116 410.15 663611666 111 661611 in Sec 4(I23 This6131116
`31161161111 13611161111p361 {If XIII: Iémfieraifimfi 111611311166 III 1111 1395113133 .1611
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`1116 (1116611011 of £116 CDIWIECIIVE enorgy 11611333111116 the opposi 16 09172111616116 to
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`3 111131111163 1133139611., The. magnitude of the temperature gradient- dopends on
`the flow- 11116 and 11161621563 with increasing flow. Strong radial temperature
`gradients (IEVEIGP near the edge of the laser beam where the available pow-61
`decreasesrapidly and are steeper near the focus where large conduction and
`radiation transport. is 164131111611 101321161166 the large powers absorbed from
`the beam. The peak temperature in the plasma occurs near focus where
`the 16561 beam intensity is maximum, and the peak temperature has a value
`that corresponds closely to the temperature, at which the first stage of ioniza»
`tion is nearly complete. The Correspondence of the maximum temporaturo
`with complete first ionization is to be expected since, for a constant pres~
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`sure 51513155., the absorption coefficient passes through a maximum at that
`temperature.
`‘
`Plasmas have been sustained by carbon diaXida lasersin a variciy’ of gases
`including the rare gases xenon, argon, and 55511 and111 55125551 51015611.»
`lar 55553 including hydrogen, (155115111111, nitrogan, 'carbon dioxide, and air.
`Plasmas in the heaviar rare gases (xenon, krypton, and argon), are the easi«
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`11151 conduction is relatively small, and 55 dissaciatiou energy 151151135 555
`plied. Few experiments have been rfiported using 1115 lightar rare gases,
`but Car'lotf at al. (1981) have sustained optical discharges in 1151111111 and
`
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