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The Sun

The energy of the sun comes from fusion of hydrogen nuclei 4H + 2e  He + 5 + 2 (+ 26 MeV). H. Bindingsenergi per nukleon. nukleoner. He. The Sun. E = mc 2 m He < 4m H + 2m e. Every second 4 million tons of mass is converted to energy. Fusion is a universal source of energy.

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The Sun

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  1. The energy of the sun comes from fusion of hydrogen nuclei 4H + 2e  He + 5 + 2 (+ 26 MeV) H Bindingsenergi per nukleon nukleoner He The Sun E = mc2 mHe < 4mH + 2me Every second 4 million tons of mass is converted to energy

  2. Fusion is a universal source of energy... ... which we would like to exploit directly on Earth

  3. Fusion on Earth D + T  n + He + 17.6 MeV Li6 + n T+He + 4.8 MeV Li7 + n  T+He +n – 2.5 MeV

  4. Fusion energy • Inexhaustible • Safe • Short-lived radioactive waste • No CO2 emission • Fuels are abundant and geographically distributed • 15 fusion power stations could cover Denmarks total energy consumption

  5. Increase of CO2 Concentrationbecomes significant Source: F. Joos, J.L. Sarmiento Phys. Bl. 51, 5, 405-411 (1995)

  6. Danes and Chinese • Denmark spends 8291015 joule / year = 26 GW • A Dane spends 166 109 joule / year = 5.3 kW • An American spends 15.9 kW • A Chines spends 0.5 kW • The Chines want to catch up, so • They open a new power station every 2 weeks! • Without drastic action • CO2 emission rate will double in 50 years, • CO2 concentration in the atmosphere will build up still faster

  7. Potential energy Nuclear forces attract Electrostatic forces repel

  8. Fusion rates Many collissions required for each fusion event In the sun a proton on average lives several billion years, fortunately. For exploitation on earth the fusion rate must be so high that the average live time is approximately 100 seconds Fusion rate = R  n1  n2 T  200 million degrees (20 times T in suns centre) n  1020/m3 P  10 bar

  9. At that temperature:Plasma

  10. Lightning is a plasma

  11. All stars and much of interstellar space are plasmas

  12. Plasmas with cold ions and hot electrons

  13. We use cold plasmas for deNOx

  14. Plasma At temperatures above 10.000 – 100.000 °C gasses turn into plasmas. A neutral mixture of ions and electrons. A plasma can be confined by a magnetic field.

  15. Magnetic configurations which can confine a plasma

  16. The Tokamak

  17. Heating methods

  18. Laser light electron Doppler frequency shift Intensity Frequency How does one measure a temperature of 100 million degrees? The width reveals the electron temperature

  19. JET: Joint European Torus

  20. JET outside Under construction in 1985

  21. 1991 JET outside NBI Lower Hybrid ICRH

  22. JET inside

  23. TEXTOR Trilateral Euregio Cluster TEC FZ-Jülich (D), ERM/KMS (B), FOM (NL)

  24. Outside TEXTOR

  25. Inside TEXTOR

  26. The system with the receiver (Catia) Figure 3. Graphical representation of the quazi-optical antenna inserted into the tokamak’s port (CATIA V5R8).

  27. ASDEX upgrade, Max Planck Institut for plasmafysik, Garching (Munchen)

  28. Plasma i ASDEX

  29. Achieved Fuion Power

  30. Energy confinement time   12 minutes  = Energy / heating power Fusion power station:  > 6 sekunder   12 hours

  31. Magnetisk Indesluttet Fusions Plasma • Achieved parameters: • Temperature (T)  200 MK • Density (n)  1020m-3 • Confinement time ()  1 sec. • n  T  1 atm sec • Target: • n  T  6 atm sec •  Must be increased

  32. Increase  Turbulence • Transport • limits 

  33. Fluktuationer

  34. The road to Fusion • ITER, science and technology of a burning fusion plasma. • Decision early 2004 • 10 years construction, • 20 years scientific exploitation • DEMO, demonstration fusion reactor • Design begins 2025 • Construction starts 2035 • Commercial fusion power 2050

  35. Burning Fusion Plasma D + T   (3.5 MeV) + n (14.1 MeV) Confined population of fast ions. Large free energy Heats the plasma Drives turbulence Affects confinement Transport What is the dynamics of the fast ions ? Can we influence it ?

  36. Fast ions are almost invisible But their wakes give them away Fast ions draw a wake in the electron fluid, Which can be detected by scattering of microwaves !

  37. Burning Fusion Plasma D + T   (3.5 MeV) + n (14.1 MeV) • Large neutron flux through the inner wall • Cause material changes: • Hardens • Swells • Becomes brittel

  38. Fusion power station

  39. Fusions-energi www.risoe.dk\euratom

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