Introduction to plasma theory and demonstration 電漿基礎理論與實作

Transcription

1 Introduction to plasma theory and demonstration 電漿基礎理論與實作 Po-Yu Chang Institute of Space and Plasma Sciences, National Cheng Kung University 2018 summer break 8/6(Mon.) 8/10(Fri.) 14:00-17:30 Lecture /8/10 updated 1

2 Course Outline 1. What is Plasma? 2. Varies kinds of plasma a. Plasma in space b. Material Processing c. biomedical application d. particle beam source e. high energy particle accelerator f. Controlled thermonuclear fusion 2

3 Outline Introduction to nuclear fusion Magnetic confinement fusion (MCF) Tokamak Stellarator Inertial confinement fusion (ICF) Indirection drive ICF Direct drive ICF Innovation idea MCF + ICF Pulsed-power system at NCKU 3

4 Outline Introduction to nuclear fusion Magnetic confinement fusion (MCF) Tokamak Stellarator Inertial confinement fusion (ICF) Indirection drive ICF Direct drive ICF Innovation idea MCF + ICF Pulsed-power system at NCKU 4

5 The iron group of isotopes are the most tightly bound 5

6 Nuclear fusion and fission release energy through energetic neutrons (3.5MeV) (14.1MeV) 6

7 Nuclear fusion provides more energy per atomic mass unit (amu) than nuclear fission Half-life (years) U x10 8 U x10 9 Tritium

8 Fusion is much harder than fission Fission: Fusion: Crosssection(barns) U+n D+T Projectile/Neutron Energy (kev) 8

9 A hot plasma at 100M ⁰C is needed Probability for fusion reactions to occur is low at low temperatures due to the coulomb repulsion force. If the ions are sufficiently hot, i.e., large random velocity, they can collide by overcoming coulomb repulsion *R. Betti, HEDSA HEDP Summer School,

10 It takes a lot of energy or power to keep the plasma at 100M ⁰C Let the plasma do it itself! The α-particles heat the plasma. *R. Betti, HEDSA HEDP Summer School,

11 Under what conditions the plasma keeps itself hot? Steady state 0-D power balance: S α +S h =S B +S k S α : α particle heating S h : external heating S B : Bremsstrahlung radiation S k : heat conduction lost Ignition condition: Pτ > 10 atm-s = 10 Gbar - ns P: pressure, or called energy density τ is confinement time 11

12 To control? Or not to control? Magnetic confinement fusion (MCF) Inertial confinement fusion (ICF) Plasma is confined by toroidal magnetic field. A DT ice capsule filled with DT gas is imploded by laser. Laboratory for Laser Energetics, University of Rochester is a pioneer in laser fusion 12

13 Outline Introduction to nuclear fusion Magnetic confinement fusion (MCF) Tokamak Stellarator Inertial confinement fusion (ICF) Indirection drive ICF Direct drive ICF Innovation idea MCF + ICF Pulsed-power system at NCKU 13

14 Charged particles gyro around the magnetic fields rr LL = mmvv qq BB 14

15 Plasma can be confined in a doughnut-shaped chamber with toroidal magnetic field Tokamak - "toroidal chamber with magnetic coils" (тороидальная камера с магнитными катушками) Drawing from the talk Evolution of the Tokamak given in 1988 by B.B. Kadomtsev at Culham. 15

16 Charged particles drift across field lines ExB drift Grad-B drift 16

17 A poloidal magnetic field is required to reduce the drift across field lines

18 A poloidal magnetic field is required to reduce the drift across field lines 18

19 There is a long way to go, but we are on the right path Dec 2025 First Plasma 2035 Deuterium-Tritium Operation begins 19

20 Stellarator uses twisted coil to generate poloidal magnetic field Tokamak Stellarator

21 Wendelstein 7-X is a stellarator built by Max Planck Institute for Plasma Physics (IPP) 21

22 Demonstration of a magnetic mirror machine 22

23 Outline Introduction to nuclear fusion Magnetic confinement fusion (MCF) Tokamak Stellarator Inertial confinement fusion (ICF) Indirection drive ICF Direct drive ICF Innovation idea MCF + ICF Pulsed-power system at NCKU 23

24 Plasma is confined by its own inertia in inertial confinement fusion (ICF) Spatial profile at stagnation 24

25 A ball can not be compressed uniformly by being squeezed between several fingers 25

26 A spherical capsule can be imploded through directly or indirectly laser illumination *R. Betti, HEDSA HEDP Summer School,

27 Rochester is known as The World's Image Center 27

28 There are many famous optical companies at Rochester Eastman school of music 28

29 Laboratory for Laser Energetics, University of Rochester is a pioneer in laser fusion OMEGA Laser System 60 beams >30 kj UV on target 1%~2% irradiation nonuniformity Flexible pulse shaping OMEGA EP Laser System 4 beams; 6.5 kj UV (10ns) Two beams can be highenergy petawatt 2.6 kj IR in 10 ps Can propagate to the OMEGA or OMEGA EP target chamber 29

30 The OMEGA Facility is carrying out ICF experiments using a full suite of target diagnostics 30

31 The 1.8-MJ National Ignition Facility (NIF) will demonstrate ICF ignition and modest energy gain OMEGA experiments are integral to an ignition demonstration on the NIF. 31

32 Targets used in ICF 32

33 Nature letter Fuel gain exceeding unity in an inertially confined fusion implosion Fuel gain exceeding unity was demonstrated for the first time. Nature 506, p343,

34 Outline Introduction to nuclear fusion Magnetic confinement fusion (MCF) Tokamak Stellarator Inertial confinement fusion (ICF) Indirection drive ICF Direct drive ICF Innovation idea MCF + ICF Pulsed-power system at NCKU 34

35 A strong magnetic field reduces the heat flux q T = κ T κ T κ κ = κ T = 0 κ χ for large Hall parameter χ l mfp R L >> 1 Typical hot spot conditions: R hs ~ 40 μm, ρ ~ 20 g/cm 3, T ~ 5 kev: B > 10 MG is needed for χ > 1 Magnetic-flux compression can be used to provide the needed magnetic field. 35

36 Principle of frozen magnetic flux in a good conductor is used to compress fields 2 Φ = π r0 B0 = π r 2 B M. Hohenberger, P.-Y. Chang, et al., Phys. Plasmas 19, (2012). 36

37 Plasma can be pinched by parallel propagating plasmas 37

38 Sandia s Z machine is the world's most powerful and efficient laboratory radiation source Stored energy: 20 MJ Marx charge voltage: 85 kv Peak electrical power: 85 TW Peak current: 26 MA Rise time: 100 ns Peak X-ray emissions: 350 TW Peak X-ray output: 2.7 MJ 38

39 Z machine 39

40 Z machine ~1 cm Stored energy: 20 MJ Peak electrical power: 85 TW Peak current: 26 MA Rise time: 100 ns Peak X-ray output: 2.7 MJ 40

41 Z machine discharge 41

42 Promising results were shown in MagLIF concept conducted at the Sandia National Laboratories t = 0 ns t = 100 ns t = 150 ns 2ω, 2 kj, 2 ns CR 20 1 cm 250 ev 1.5 mg/cc The stagnation plasma reached fusion-relevant temperatures with a 70 km/s implosion velocity S. A. Slutz et al Phys. Plasmas (2010) M. R. Gomez et al Phys. Rev. Lett (2014) 42

43 Neutron yield increased by 100x with preheat and external magnetic field. M. R. Gomez et al Phys. Rev. Lett (2014) 43

44 There are alternative 44

45 P-B 11 is much more difficult to occur than D-T fusion 45

46 Field reverse configuration is used in Tri-alpha energy *Magneto-Inertial Fusion& Magnetized HED Physics by Bruno S. Bauer, UNR & Magneto-Inertial Fusion Community ** 46

47 Field reverse configuration is used in Tri-alpha energy 47

48 General fusion is a design ready to be migrated to a power plant 48

49 Tokamak energy Ltd

50 Merging compression is used to heat the plasma 50

51 The performance of a fusion plasma has doubled every 1.8 years like the Moore s law 51

52 We are really closed! Phys. Plasma 17, (2010) 52

53 Neutral beam source Neutral beam injection for heating plasma in Tokamak Jure Maglica, Seminar at University in Ljubljana Ian G. Brown, The Physics and Technology of Ion Sources Electric propulsion (plasma thrusters) D. M. Goebel and I. Katz, Fundamentals of Electric Propulsion: Ion and Hall Thrusters 53

54 Hot plasma is confined by the magnetic field in magnetic confinement fusion

55 Neutral beam injector is one of the main heat mechanisms in MCF ηη TT 3 2 D. Mazon, etc., NATURE PHYSICS, 12, 14,

56 Varies way of heating a MCF device Nuclear Fusion, 39, 2495,

57 Neutral particles heat the plasma via coulomb collisions 1. create energetic (fast) neutral ions 2. ionize the neutral particles 3. heat the plasma (electrons and ions) via Coulomb collisions 57

58 Negative ion source is preferred due to higher neutralization efficiency 58

59 NBI for ITER beam components (Ion Source, Accelerator, Neutralizer, Residual Ion Dump and Calorimeter) other components (cryo-pump, vessels, fast shutter, duct, magnetic shielding, and residual magnetic field compensating coils) 15 m 9 m 5 m The ITER neutral beam system: status of the project and review of the main technological issues, presented by V. Antoni 59

60 Neutral beam penetration Parallel direction Longest path through the densest part of the plasma Harder to be built Perpendicular direction Path is short Larger perpendicular energies leads to larger losses Easier to be built 60

61 Neutral beam source Neutral beam injection for heating plasma in Tokamak Jure Maglica, Seminar at University in Ljubljana Ian G. Brown, The Physics and Technology of Ion Sources Electric propulsion (plasma thrusters) D. M. Goebel and I. Katz, Fundamentals of Electric Propulsion: Ion and Hall Thrusters 61

62 Comparison between liquid rockets and ion thrusters Liquid rockests u~4500 m/s Isp~450 s Energy ~ 100GJ Power ~ 300MW Thrust ~ 2x10 6 N Ion thrusters u~30000 m/s Isp~3000 s Energy ~ 1000GJ Power ~ 1kW Thrust ~ 0.1 N 62

63 Electric thruster types - electrothermal Resistojet Arcjet 63

64 Electric thruster types - electrothermal Ion thruster Hall thruster 64

65 Electric thruster types - Electromagnetic Pulsed plasma thruster Magnetoplasmadynamic thruster (MPD) 65

66 Ion thruster has the highest specific impulse (Isp) 66

67 A pulsed-power system is being built in ISAPS, NCKU 2200 mm 4300 mm 600 mm 160 mm 50 mm 140 mm 100 mm 1745 mm 67

68 Capillary z pinch discharge for generating soft x-ray laser Ne-like Ar soft x-ray lasing (λ = 46.9 nm) can be generated. Y. Hayashi et al. Plasma Sources Sci. Technol. 13 (2004)

69 Soft x-ray laser can be made with table-top pulsedpower system Lasing Capillary length: 200 mm Capillary inner diameter: 3 mm Capillary material: Al 2 O 3 ceramic Filled gas: 200~500 mtorr Ar Capillary is pre-discharged by a current up to 20 A. Discharge current: up to 32 ka Ne-like Ar lasing at 46.9 nm (sub mmj/pulse) The light source can be used for lithography. Y. Hayashi etc., Plasma Sources Sci. Technol., 13, 675 (2004) C. D. Macchietto etc., Optics Lett., 24, 1115 (1999) 69

70 Different wire configurations can be used to generate plasma jets and hard x rays x pinch multi-wires x pinch wire array conical-wire array inverse-wire array radial-wire array radial foil 70

71 Spatial coherent hard x rays can be generated using x pinches for point-projection x-ray radiography x pinch The process of an exploded x pinch Point-projection x-ray radiography We are expecting x-ray yields of couple kev, < 1ns, <10 um, ~5 J in total energy generated in our system. * G. V. Ivanenkov et al. Plasma Physics Reports 34, 619 (2008) * T. A. Shelkovenko et al. Plasma Physics Reports 42, 226 (2016) * T. A. Shelkovenko et al. IEEE Trans. Plasma Sci. 34, 2336 (2006) * D. H. Kalantar et al. J. Applied Physics 73, 8134 (1993) 71

72 Soft x rays for 3-D x-ray tomographic microscopy can be generated using gas-puff z pinches Line radiation in the range of Å ( ev) with a total energy of 10 J using CO 2 is expected. Anode Gas-puff Cathode Soft x rays (~520eV) from synchrotron radiation at Advanced Light Source (ALS) is used for 3-D x-ray tomographic microscopy. 0.5 um Single line emission in 41.8 / 32.8 nm is expected using Xenon or Krypton. *P. Choi et al. Rev. Sci. Instru. 57, 2162 (1986) *G. Nave et al. J. Appl. Phys. 65, 3385 (1989) *M. Uchida et al. Proc. National Acad. Sci. 106, (2009) 72

73 Plasma jet can be created for laboratory astrophysics and space science A conical-wire array can be used to generate a plasma jet where the flow speed is 200 km/s with Mach number up to 20. The solar wind is a supersonic plasma flow with Mach number 5-10 and the flow speed 400 km/s. * S. V. Lebedev et al. Astrophys. J. 564, 113 (2002) * George K. Parks, Physics of Space Plasmas: An Introduction (Perseus Books (Sd), 1991). 73

74 Hydrodynamic equations can be written in a dimensionless form Dimensional form: + ρρ uu = 00 ρρ uu + uu uu = + uu = γγγγ uu Dimensionless form: ρρ ~ tt ~ + ρρ ~ ~ uu = 00 ρρ ~ ~ uu tt ~ + ~ uu pp ~ ~ uu ~ tt ~ + uu = pp ~ pp ~ = γγpp ~ uu ~ Any two hydrodynamic systems involve identically in a scaled sense if f, g, h, and u*(ρ*/p*) 1/2 are the same. rr ~ = rr LL ~ tt tt = LL ρρ ~ = ρρ ρρ pp ~ = pp pp uu ~ pp ρρ = uu pp ρρ ρρ ~ 00 rr ~ = ff rr ~ pp ~ 00 rr ~ = gg rr ~ ~ uu ~ 00 rr = pp ~ hh rr ρρ 74

75 Interactions between solar winds and planetary magnetic fields or unmagnetized planets will be studied Electrically nonconductive planets Electrically conductive planets w/o B Electrically conductive planets w/ B Ex: moon Ex: mars or venus Ex: earth Lucy-Ann McFadden and Torrence Johnson and Paul Weissman, ed., Encyclopedia of the Solar System, 2nd Ed. (Academic Press, 2006). 75

76 Reconnection can be simulated experimentally using pulsed-power machine * James L. Burch and James F. Drake, American Scientist 97, 392 (2009) * Lucy-Ann McFadden and Torrence Johnson and Paul Weissman, ed., Encyclopedia of the Solar System, 2nd Ed. (Academic Press, 2006). 76

77 An Dense-Plasma-Focus (DPF) device is a pulsed-power device that can generate high-energy electrons and ions, x rays, and neutrons A 6 kj DPF device can generate 3x10 8 neutrons in each discharge and is a very attractive neutron source. It can be a table-top neutron source for (Boron) Neutron capture therapy of cancer ((B)NCT). Plasma Sources Science and Technology, 13(2):272,

78 BNCT is a biologically and a physically targeted type of radiation therapy Mean free paths of the generated particles are less than 10 um which is shorter than a single cell. Energy is deposited to the neoplastic cell and ravaged. J. Clin. Diagn. Res., 10(12) ZE01,

79 A toroidal plasma is generated for demonstration 79

80 Summary Plasma is everywhere and has many applications What is a plasma? Important plasma parameters Debye length, Plasma parameter, Plasma frequency Space science Aurora / Reconnection / Corona mass ejection / DC electrical discharges Dark / glow / arc discharges AC electrical discharges RF / Microwave discharges / Electron cyclotron resonance (ECR) plasma Semiconductor device fabrication etching / deposition / implantation 80

81 Summary Plasma is everywhere and has many applications High energy particle accelerator Plasma medicine dielectric barrier discharge (DBD) Nuclear fusion MCF / ICF / Innovation Neutral beam source Neutral beam injection (NBI) / Electric propulsion Pulsed-power system in ISAPS, NCKU 81

82 Summary Demonstration you have seen in this class a. Planeterrella b. Magnetron sputtering c. Dielectric barrier discharge (DBD) d. Magnetic mirror e. Tokamak Planeterrella Magnetron sputtering DBD plasma Magnetic mirror 82

83 深入的電漿知識請選修電漿學分學程 未修過四大類課程的學生 必修選修 半導體製程類 太空科學類 理論基礎課程 生醫光電類 核融合與工程類 將培養具備電漿科技研究與產業應用等多元專業且更具競爭力之跨領域人才. 83

84 Acknowledgement - all experimental demonstrations were developed by my students from scratch 陳國益 鄭名城 84

85 Acknowledgement - all experimental demonstrations were developed by my students from scratch 陳國益 鄭名城 85

86 Grading Attendance 25 % Assignments 25 % Final report 50 % Pick a plasma application or plasma application/phenomenon. Explain in details how the application/phenomenon works. Where the application/phenomenon is used or occurs? How is the plasma generated in the application/phenomenon? What role does the plasma play in the application/phenomenon? The writing part of the report needs to be longer than two full pages with font size 14 and single-line spacing. 86