2. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 JET: A major scientific contribution to the conception and design of ITER Prof. Francis Troyon Ex Chairman of the JET Scientific Council Ex Member of the ITER TAC former Director CRPP EPFL 25th JET Anniversary, Culham 20th May 2004

3. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 The Outstanding Features of the JET concept D-shaped configuration (vessel elongation  =1.6) Largest size in the world (volume vacum vessel about 180x that in largest existing tokamak) Highest current (12x) Fully compatible with DT operation Conservative engineering

4. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 INTOR-Zero Parameters (1980) D-shaped plasma (  =1.6) with divertor R=5.2 m a=1.3 m I=6.4 MA B=5.5 T Density 1.4-1.5 10 20 m -3 (tentative) Beta=5-6% (tentative)

5. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 ITER Overall Objectives Demonstrate the scientific and technological feasibility of fusion energy for peaceful purposes

6. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 ITER-RC detailed technical objectives (extract) Achieve extended burn with Q>=10 during enough time to reach stationary conditions for plasma physics processes Aim at demontrating steady-state operation at Q>=5. Not preclude ignition

7. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 ITER Performance Specifications Adress issues of burning plasma experiments: confinement, stability, exhaust of helium ash and impurity contrôle in discharges with dominant alpha particle heating Profile control and all mean to control profile and burn Identify sufficiently reliable operating modes for nuclear testing

8. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 2.5%, 0.7  T,  P 10Q (P fus /P in ) 80+P  (MW) 40-90P aux (MW) 0.5, 1.85 ,, 5.3B t (T) 15(17)I P (MA) 850V P (m 3 ) 2a (m) 6.2R (m) ITER

9. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 Plasma cross section Divertor

10. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 L-Mode scaling

11. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 Different tokamak operating modes

12. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 H-Mode scaling

13. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 Operational limits Elongation  < ≈ 2 Current I  B  a 2 /R 2 Pressure limit  IB/a Density limit n  I/a 2 But can these limits be pushed ?  Advanced scenarios The most favourable factors for confinement have limits. Performance will then depend on how close operation is possible near these limits:

14. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 ITER Operational diagrams

15. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 JET D-T Operation Confirmation of good confinement scaling Effect on P L-H simple but good !! Demonstration of standard ITER scenario in steady state (ELMy H-Mode) without impurity accumulation Fast  particles heat the plasma without being lost Succesful demonstration of exhaust of thermal  -particles on JET done

16. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 D-T Confinement scaling in JET

17. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 SCENARIO CHOSEN FOR Q ~ 10 OPERATION ON ITER 4.5 MW Fusion Power Demonstration of steady state ELMy H-Mode in D-T

18. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 From JET to ITER

19. Prof. F.Troyon“JET: A major scientific contribution...”25th JET Anniversary 20 May 2004 JET was a giant step when designed and built JET served as the model for the design of all next step machines, including ITER Without JET, what would ITER be today ?? JET remains the essential machine to test any new concept for ITER in which size and performance is important JET is an essential tool to study the « high reward » concepts (Advanced Scenarios) to further increase the operational domain and the identification of reliable operating modes for nuclear testing Conclusions