The Burning Plasma Experiment and International Collaboration

1. The Burning Plasma Experimentand International Collaboration S. C. Prager University of Wisconsin April, 2003

2. What is a burning plasma? A self-sustaining, self-heated plasma; High temperature maintained by heat from fusion; Analogous to a burning star

3. Two approaches to fusion energy • inertial confinement, magnetic confinement • Magnetic confinement international collaboration since 1958, development of plasma physics as a new field, now ready for frontier of burning plasmas, new challenge for international collaboration

4. Burning Plasmas • plasma physics challenge to • Understand a burning plasma • Create a burning plasma Fusion power density in sun ~ 300 Watt/m3, in burning plasmas experiment ~10 MWatt/m3

5. A burning plasma requires a large experiment either • Large, but “domestic-scale” (~$1B) FIRE or • Larger, “international-scale” (~$5B) ITER Choices: domestic vs international, large vs larger

6. Outline • Fusion research - why? Status? • Burning plasmas - physics challenges • Experimental options - ITER, FIRE • US strategy

7. Why Fusion Energy Research? For fundamental plasma physics For fusion energy • Clean - no greenhouse gases, no air pollution • Safe - no catastrophic accidents • Inexhaustible - fuel for thousands of years • Available to all nations

8. The fusion reaction D + T n +  10 keV14 MeV3.5 MeV The Fusion Challenge Confine plasma that is hot (100 million Kelvin) dense (~1014 cm-3) well-insulated (~1 sec energy loss time) several atmospheres

9. Status of Fusion Research More than half way there, judging from • Plasma parameters • Physics understanding • Timetable

10. Huge advance in plasma parameters fusion power year

11. The burning plasma regime is a reasonable extrapolation from current experiments

12. Establishing the physics basis Fusion plasma physics developed for example, control of turbulence and energy loss understanding of pressure limits We are ready for a burning plasma experiment

13. A burning plasma is self-heated by alpha particles D + T n +   particles trapped in plasma,  particles heat plasma Generates large amount of fusion power

14. prior plasma experiments • Mostly operated without fusion fuel - no tritium • Plasmas heated by external means • Exceptions - JET (EU) and TFTR (Princeton) generated 16 MW for 1 sec alpha particle heating, but weak ITER will produce 500 MW for 300 sec 350 MW for 3000 sec

15. Why burning plasmas? • New physics • New technology • Demonstration of fusion power

16. Burning Plasma Physics New physics from alpha particles • Effects on stability and turbulence • Alpha heating and burn control

17. Effect of alpha particles on plasma stability Kinetic energy of alpha particles Plasma waves Loss of alpha particles Plasma cools

18. The Alfven Wave in an infinite, uniform plasma vphase = vAlfven where vAlfven ~ B Phase velocity spectrum vphase

19. in a torus vphase waves driven by wave-particle resonance Alpha particles excite wave, Wave scatters alpha particles out of plasma

20. Alpha Heating and Burn Control temperature reaction rate thermal stability

21. add a little alpha physics, temperature reaction rate heating by alphas Alfven waves loss of alphas

22. add some more physics Alpha ash accumulation turbulence transport temperature reaction rate Alfven waves heating by alphas loss of alphas resonance etc A burning plasma is a strongly coupled system

23. Burning Plasma Technology • Plasma technology Materials for high heat fluxes High field magnets Plasma control tools • Nuclear technology Blankets for breeding tritium Materials for high neutron fluxes

24. Experimental Approaches to Burning Plasmas FIRE Fusion Ignition Research Experiment Burning, but integration later US based (~ $1B) ITER International Thermonuclear Experimental Reactor Integrates burning and steady state International partnership (~ $5B)

25. The History of ITER 85 discussions begin (Reagan/Gorbachev summit) 88 - 91 Conceptual Design Activities (European Union, Japan, Soviet Union, US) 92 - 98 Engineering Design Activities 99 US withdraws 98 - 01 Design of reduced cost ITER (50%) 02 Four sites proposed 03 US, China join negotiations Ready to build, negotiations underway on site and funding

26. ITER Characteristics Strongly burning plasmas in near steady-state conditions strongly burning: 500 MegaWatts fusion power gain ~ 10, ~ 70 % heating by alphas Near steady state: 300 to > 3000 seconds, many characteristic physics time scales. technology testing, power plant scale

27. plasma current ~15 Meg Amps,magnetic field ~5 Tesla/SC, temperature ~ 100 million Kelvin, density ~ 1014 m -3

28. Proposed ITER Sites

29. Approximate ITER schedule • Select site 2003 • Authorize construction 2004 - 5 • Construction to first plasma ~ 8 years • Begin operation ~2015

30. FIRE Characteristics Stronglyburning plasmas in quasi-stationary conditions strongly burning: 150 MegaWatts fusion power gain ~ 10, ~ 70 % heating by alphas quasi-stationary: ~ 20 - 40 seconds, several characteristic physics time scales FIRE is comparable in size to existing tokamaks

31. FIRE plasma current ~8 Meg Amps,magnetic field ~10 Tesla (Cu), temperature ~ 100 million Kelvin, density ~ 5 x 1014 m -3

32. FIRE and the International Program Envisioned as part of multi-machine strategy • Burning plasmas in FIRE • Steady state in non-burning plasma (e.g., KSTAR in S. Korea, JT-60 SC in Japan) Integrate at later stage, employing new knowledge and innovation from full fusion research

33. FIRE Status • Design scoping studies underway • National effort > 15 participating institutions • Preparing to start design in 2005 • Can be sited at one of the existing US labls

34. The US Strategy for Burning Plasmas Recommended by the Fusion Energy Sciences Advisory Committee (Sept, 02) based on • Three community workshops • A 2 week community technical assessment • Recommendations of 40 person FESAC panel The strategy is the strong consensus of the fusion community

35. Basis for the strategy • ITER and FIRE are each attractive options for the study of burning plasma science. • Each could serve as the primary burning plasma facility, although they lead to different fusion energy development paths • Because additional steps are needed for the approval of construction of either FIRE or ITER, a strategy that allows for the possibility of either burning plasma option is appropriate

36. Recommended Strategy for US Join ITER project; if no go, then build FIRE US Participates in ITER yes Terminate FIRE project Join ITER negotiations ITER will be constructed? No Build FIRE, Notes: advance FIRE design until US ITER decision recommended conditions for US participation, set time deadline for US ITER decision (~ 7/04)

37. Recommendation on IGNITOR based in Italy If IGNITOR is constructed in Italy, then the US should collaborate in the program by research participation and contributions of related equipment

38. The Role of International Collaboration( in executing a large project) The good • Cost sharing: essential beyond some cost • Sharing of ideas, even in project conception • International political support: provides stability • International management and execution: a useful experiment, facilitates additional joint activities

39. The challenges • Joint international management and decision-making (site selection, cost-sharing, procurement,…….) • Need for international political support (need approval and sustainment from multiple governments) International partnership to build a multi-billion dollar science facility may be without precedent

40. Fusion community perspective • Ready/anxious to study burning plasmas • Neutral to whether international or domestic in management • The net result of the political pluses and minuses in unknown • Any burning plasma experiment will have strong int’l collaboration • Any burning plasma experiment will have huge scientific benefit for all nations; and establish the scientific feasibility of fusion energy.