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University of the South - Nov. 12, 2014


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Focus Fusion: the Fast Route to Fusion Energy Systems was a presentation given by LPPFusion's Chief Scientist, Eric J. Lerner, on Nov 12, 2014 at University of the South.

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University of the South - Nov. 12, 2014

  1. 1. E. J. Lerner, Chief Scientist, LPPFusion, Inc. Nov 12, 2014 Focus Fusion: the Fast Route to Fusion Energy Systems University of the South LPPFUSION
  2. 2. What Would Happen If We had Cheap Clean Energy? What if we could develop in the next five years a 5 MW energy source 10 times cheaper than any now available that was safe and non-polluting?
  3. 3. Economic Benefits 17% increase in real income for median industrialized country resident 44% increase in real income for median person in the world
  4. 4. JOBS, Services and Infrastructure $5 TRILLION per year not spent on energy 100-150 million new jobs globally
  5. 5. Environmental Benefits • End 7 million deaths per year from pollution by coal, diesel, gasoline • End oil spills, mining devastation • Total recycling with plasma torch • Money released to end deforestation, environmental clean-up • No greenhouse gases • No radioactive waste
  6. 6. Benefits for Peace No more war to prop up the price of oil Fission energy is obsolete— lock up the uranium mines
  7. 7. Distributed Power • 5 MW generators, safe enough to put in neighborhoods • far more reliability in disasters, • rapid deployment to towns and villages throughout the world
  9. 9. Dense Plasma Focus : small inexpensive device
  10. 10. FOCUS FUSION – 1, Experimental Device
  11. 11. Focus-Fusion-1 Experimental Device 12-CAPACITOR BANK Stored energy 100kJ (vs 10 GJ for JET) Capacitor potential 45 kV Peak current 1.4-2.8 MA Electrodes: 5 cm cathode, 2.8 cm anode
  12. 12. How could we possibly be so small and fast? 1) Magnetic fields supplied by currents not external magnets 2) Use natural instabilities, not fight them 3) Seeking metastability, not absolute stability—far easier
  13. 13. Physics of the DPF Parallel Currents Attract : Pinch Effect Ampere and the Pinch Effect
  14. 14. Key Concepts How Do We Know the Magnetic Field? Ampere’s Law How Do We Know the Force? Lorentz Force Law
  15. 15. Physics of the DPF Ampere’s law Ampere-1826 Maxwell—1864 Heaviside 1884-89 • The curl of the magnetic field at any point is proportional to and in the same direction as the rate of change of the electric field with time plus the current density (current per area).
  16. 16. Meaning of the curl Imagine the magnetic field as a flow of fluid in the direction of the magnetic field at every point. Then If your fingers of the right hand are in the direction of the flow then your thumb defines the axis the fluid is spinning – the direction of the “curl” –and the rate of spin is the magnitude of the curl. The current density gives the curl of the field and the curl lets us calculate the magnetic field
  17. 17. Lorentz Force Law Heaviside 1889 Lorentz 1892 F=q(E + vXB) Force on a charge is equal to the charge q times the sum of the electric field strength and the cross product of the particle’s velocity and the magnetic field strength
  18. 18. How A DPF Device Works
  19. 19. Magnetic Field of DPF
  20. 20. Unpinch, Rundown, Pinch
  21. 21. Force-Free Vortex Filaments 1950-1963
  22. 22. Key plasma parameters-- such as velocity--are scale-invariant In Lab: 10 cm , msec Solar flare: 10,000 km, 100 sec Galaxy: 30 kpc, 15 My Super-cluster: 100 Mpc, 100Gy The Cosmic Connection Alfven, Falthammar
  23. 23. Spiral GalaxyQuasars Beam From Star Formation REPRODUCING NATURAL INSTABILITIES Solar Flares
  24. 24. PLASMOID 8ns after pinch
  25. 25.
  26. 26. Metastability Far Easier High Density, High B field ITER DPF Minor radius cm 200 6x10-4 Ion velocity 108cm/s 1.2 10 B Field 5x104 5x109 Ion density 1014 1024 Confinement time 400 s 6 ns Ion revolutions 4x107 1.6x103 25,000 times easier
  27. 27. What Is Aneutronic Fusion? It’s a fusion using aneutronic fuel, ideally made of hydrogen and boron, pB11, which produces no neutrons and thus no radioactive waste. Aneutronic → No neutrons → No Radioactive waste LPPHYSICS.COM
  28. 28. Faraday’s Law Faraday 1831 The curl of the field is proportional to and in the opposite direction from the rate of change of the magnetic field with time.
  29. 29. ENERGY CAPTURE DEVICE X-rays, Ion Beams
  30. 30. SAFE • NO neutrons from main reaction • NO high energy neutrons • NO radioactive waste—electrodes contain less radioactivity than a roomful of people. • Generator safe to service without protection 9 hours after turn-off
  31. 31. How Safe? • 0.8 micro curies of radioactivity in each used set of electrodes. • Radioactivity of human child –about 0.2 micro curies Radioactivity of classroom of 25 children—5 micro curies • NO RADIOACTIVE WASTE
  32. 32. Aneutronic DPF Allows Far Higher Energy Density, Far Lower Cost ITER Focus Fusion Power (MW) 500 5 Power/m3 0.05 1200 Power/m2 0.5 40 Neutron power/m2 0.5 0.08
  33. 33. Fusion Comparison Fusion Yield/Energy Input Energy output per 1,000 J input DT: DD: JET 2.2 J 0.01 J Sarov DPF 0.2 J 0.00045 J NIF 0.03 J FF-1 DPF 0.004 J
  34. 34. WHERE ARE WE? Ion temperature— goal achieved —over 1.8 billion degrees, enough to ignite pB11 Confinement time— goal achieved 20 ns—more than 8 ns goal Energy transfer to plasmoid— over 50% of goal Density—must increase by 10,000
  35. 35. Steps To Increase Density 50x-- Achieve theoretical density—tungsten electrodes to eliminate impurity 10x-- Increase current to 2.8 MA 20x-- Better compression with heavier pB11
  36. 36. How Do we Reduce X-ray Cooling? X-ray emission increases as z2 Boron 25 x as emissive as hydrogen How do we avoid this?
  37. 37. Reducing X-ray Cooling Quantum Magnetic Field Effect
  38. 38. Quantum Magnetic Field Effect 2003 QMEF reduces Te by >20x Cuts X-ray by >4x Allows ignition of pB11 BUT only with B>~3 GG
  39. 39. Ion energy of 160 keV
  40. 40. Generated Interest
  41. 41. How Does it Get so Hot? Main Mechanism is Viscous Heating—Haines, others Ordered Motion Into Random Motion Higher Densities, Electron Beam Wave Heating
  42. 42. Why Does DPF Fusion Yield Plateau? LPPHYSICS.COM y = 1E-08x6.7542 1.00E+06 1.00E+07 1.00E+08 1.00E+09 1.00E+10 1.00E+11 1.00E+12 1.00E+02 1.00E+03 NeutronYield Current I (kA) Buenos Aires(PFI) FF-1 Frascati(1MJ) Limeil NTSC Swierk U of Illinois LPP Stuttgart(HV) Darmstadt Stuttgart(Poseidon)
  43. 43. Sources of Impurities: Erosion of Anode, Arcing at Joins Amounts: 0.6mg from anode erosion, 0.4mg from arcing 50% of D sheath mass LPPFUSION
  44. 44. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 34 35 36 37 38 39 40 41 Impurity/Dmassratio Charging voltage (kV)
  45. 45. LPPHYSICS.COM Uneven impurity distribution (2012) asymmetric sheath poor compression Increase in collision rate with zeff 4 (2013) prevents magnetization of filaments leading to double sheath Low Density Yield Plateau
  46. 46. What We Should See
  47. 47. What We Actually See
  48. 48. New-2014 Cause of Anode Erosion: Runaway Electrons (PHYSICS OF PLASMAS 21, 102706) During breakdown, with high E fields Vre=5.5e(E/40p)^1/2 eV (Tarasenko and Yakovlenko) Vaporization occurs if thermal conduction can’t carry away heat at the boiling point e(E/40p)^1/2 eV> 0.22LwT(rEtC/t) 1/2/I
  49. 49. Why More Effect with Higher Current? 1) Arcing above 2 MA/cm2 2) Magnetization of filaments easier to disrupt Magnetization depends on B/n. For B2/n constant, B/n declines with increasing B
  50. 50. Monolithic Electrodes Connected Outside Chamber Solution to Arcing
  51. 51. Getting the B Field • FF-1Now– 0.06 GG With filaments—0.6 GG Full current—1.3 GG With pB11—10 GG
  52. 52. Needed: Beryllium electrodes Tungsten is fine for impurity, but absorbs too many x-rays Beryllium far more transparent But costs-- (single unit)--$120,000
  53. 53. Biggest Engineering Challenges Heat Removal—Electrode Erosion • Sputtering may limit electrode lifetime but with re-deposition a few weeks may be OK • Anode will be heated by x-rays - key upper limiting factor in repetition rate • Deposition of boron - key lower limit on repetition rate
  54. 54. Why Has it Taken So Long? Massive Underfunding: Tungsten too expensive Too few large experiments Under staffing slows progress