1. Extrapolation of GDT Results to a DT Fusion Neutron Source for Fusion Materials Testing e Tom Simonen, U. Calif., Berkeley 8 th International Conference on Open Magnetic Systems July 5-9, 2010 Novosibirsk, Russia

2. US Fusion Program (2010) Establish the Scientific Basis – Burning Plasma (ITER) – Plasma Control (DIIID, EAST,KSTAR, JT60) – Materials Science Plasma Material Interactions Neutron Material Interactions ………..

3. US Mirror Assessment Stimulated by new Gamma-10 and GDT Results Formed a Mirror Study Group (Virtual Meetings) – 10 Institutions, 25 individuals Held Two Workshops – Physics and Technology Held a Magnetic-Mirror Mini-Conference – At 2009 American Phys. Society DPP Meeting – Participated in Numerous DOE Planning Meetings Proposed International Collaborations – Russia, Japan, China Tutorial Talk at 2010 APS Meeting – Dmitri Ryutov

4. ITER is under Construction China, EU, India, Korea, Japan, Russia, US (

5. FUSION CHALLENGES (Sci.Am., March 2010) “Before fusion can be a viable energy source, scientists must overcome a number of problems. Heat: Materials that face the reactions must withstand extremely high temperatures for years on end. Structure: The high-energy neutrons coming from fusion reactions turn ordinary materials brittle. Fuel: A fusion reactor will have to “breed” its own tritium in a complex series of reactions. Reliability: Laser reactors produce only intermittent blasts; magnet based systems must maintain a plasma for weeks, not seconds.”

6. Fusion Neutrons Damage Materials

7. Fusion Materials Must Withstand Neutron Bombardment Three Options toQualify Materials: – Accelerator Based (coupons) – Mirror Based (Blanket Sub-modules} – Tokamak Based (Blanket Modules)

8. RTNS Accelerator Facility (US Rotating Target Neutron Source)

9. RTNS Accelerator

10. IFMIF Design by EU & Japan

11. Tokamak Component Test Facility (US Design)

12. Tokamak Fusion Nuclear Science Facility (US Design) fnsf

13. TDF 1980’s Mirror Based Neutron Source Designs

14. Axisymmetric Magnetic Mirror Gas Dynamic Trap (GDT) Concept A.A. Ivanov, Fus. Sci. & Tech. 57, (2010), 320

15. GDT Schematic

16. GDT DD-Neutron Axial Profile (Agrees with Computer Simulation)

17. Electron Temperature vs Time ( End Expansion = 100) 17 - H-plasma n ≈ 1.5 x 10 13 cm -3 with H-NBI - H-plasma n ≈ 2.5 x 10 13 cm -3 with H-NBI - D-plasma n ≈ 2.5÷3 x 10 13 cm -3 with H-NBI - H-plasma n ≈ 1.2 x 10 13 cm -3 with H-NBI min gas puff - H-plasma n ≈ 3 x 10 13 cm -3 with D-NBI - H-plasma n ≈ 3.5÷3 x 10 13 cm -3 with H- NBI

18. Neutron Flux Increases with Te (Now GDT Te = 0.25 keV so Flux = 0.4 MW/m 2 ) (ITER Goal = 0.5 MW/m 2, Fluence = 0.3 MW-yrs/m 2 )

19. A Russian Neutron Source Design A MW of Fusion Power for Weeks Neutron Flux ~ 2 MW/m2 Test Area ~ 1 m2 I

20. A DTNS Showing Magnets, Shielding,Neutral Beams, and Material Samples (Bobouch, Fusion Science & Tech. 41 (2002) p44)

21. With Today’s GDT ElectronTemperature (0.25 keV) DTNS Neutron Flux 80% of ITER DTNS Neutron Fluence in One Year Exceeds that in ITERs Lifetime Note: DTNS does Not Address ITER’s Burning Plasma Physics or Full-scale Blanket Module Testing

22. Design DTNS from GDT Results Same Physical Size – L, r Higher Mag. Field, NBI Energy and Power – 1.2 T, 80 keV, 40 MW Same Dimensionless Parameters – Beta, B(z), L/ai, r/ai, Te/Ei

23. Same-Size & Dimensionless Scaling GDTDTNS B, Tesla0.31.0 Eb, keV2080 Pb, MW530 Beta (%)60 Mirror Ratio, R17 Length, & Radius, cm7 00, 6 Radius / Gyro-radius22 Debye Length, 10-3 cm22 Te/Eb, %11 Collisionality51 Marginal f(pe)/f(ci)60.6 More Microstable v(b)/v(Alfven)1.60.5 More Alfven Stab

24. A Possible Next Step A Phased Approach (Physics >> PMI >> D-T Neutrons) B = 0.6 Tesla – 1 s NBI 40 keV – 1 MW – 1 s

25. Key DTNS Scientific Issues Increase Electron Temperature – Now Te ~ 0.25 keV (0.4 MW/m 2 neutrons) – Demonstrate Te > 0.5 keV (80 keV NBI) Confirm MHD Stabilization Physics – Diagnostics and Simulation Evaluate DTNS Design – Simultaneous Neutron and PMI Testing?

26. Key DTNS Technical Issues High Neutral Beam Power Large Tritium Recycling Consider Simple Tandem-Mirror Concept (GDT-SHIP concept) Small Axisymmetric End-Cells Reduce Plasma End Losses – Reduces overall neutral beam power – Reduces Tritium Recycling

27. A Tandem-Mirror Neutron Source (TNS) (Based on TMX Data and the GDT-SHIP Concept)

28. TNS Features Plug to Center-cell density ratio4 – To reduce end loss 4-fold Plug Mirror ratio3 – To reduce AIC and loss cone size Plug NB injected at mirror ratio 1.3 – For AIC Stability Neutral Beam Power (MW)20 – Half of DTNS

29. TNS Parameters Maximum Miagnetic Field, 20 Tesla Plug Mirror Ratio, 3 Central-Cell Magnetic Field, 1.2 Tesla Central-Cell NBI Power, 10 MW End-Cell NBI Power, 5 MW each Electron Temperature, 2 keV

30. TNS Challenges ( GDT-SHIP can address many issues) Electron Temperature MHD Stability at Higher Te Energetic Ion iMicro-stability Tritium Retention Detailed Modeling Needed GDT – SHIP can address many issues

31. Summary A DT Neutron Source (DTNS) can have the same Physical-Size and the same Dimensionless -Size as GDT A Simple Tandem Mirror Neutron Source (TNS) Reduces Tritium Reprocessing 4-fold and Reduces the Neutral Beam Power 2-fold.

32. We Can Produce 1 MW of Fusion Power Sustained for Weeks within 10 Years Purpose: – Test materials & Subcomponents – Demonstrate sustained fusion power Features: – Based on recent GDT Results – Low Tritium Consumption, – No tritium Breeding Required – Simple Construction Geometry.