Status report on JET

1. Status report on JET M. L. Watkins 22nd Meeting of the Executive Committee of the IEA Large Tokamak Implementing Agreement Naka, Japan, 21-22 May 2007

2. JET since LTA ExCom21, Cadarache, 2006 • Completed four Experimental Campaigns comprising 103 S/T days (two shift operation during Autumn 2006 – Spring 2007): • C16&C17 from 25 September to 15 December 2006; and • C18&C19 from 8 January to 4 April 2007 • Carried out 32 ITPA High Priority Coordinated Experiments (~35 S/T days) • Utilised high power NB, LHCD and ICRF at a distance, upgraded diagnostics,TF Ripple, Error Field Correction Coils… • Procured, assembled and tested enhancements for installation during 2007 (ITER-like ICRH Antenna, High Frequency Pellet Injector,…) • Conducted R&D, procured components and buildings for enhancements for installation during 2009 (ITER-like Wall, NB Power Upgrade,…) • Conducted Fusion Technology Tasks using the JET Facilities

3. Participation in JET programme 2006/7 On-site participation by 294+243 staff (43+27ppy) from Europe,37+27+2 scientists (615+328ppd+2ppy) under International Collaborations

4. Types of on-site visits, 2006 (%) 100% = 306 ppd Hardware and its exploitation 16 18 Key competencies Modelling & software 31 Experiments 35 United States International collaboration, 2006 Additionally, two full-time US collaborators On-site effort provided (ppd) No. of scientists 306 25 United States Important role of international collaborationsrecognised by EFDA Committees 286 9 Russian Federation 23 3 Japan

5. 160 P > 20 MW 140 tot 140 120 100 In addition, several pulses with Ptot>30MW Number of pulses 80 60 40 29 24 20 20 5 2 0 0 0 0 0 0 0 0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year JET high NB power pulses (1994-2006)

6. Extended performance at high  in 2006/7 2006 AT data at high d : HH<1.1 4 bN 2009 extension High bN1.8T 1.2MA High bN2.3T 1.5MA High bp2.7T 1.2-1.5MA 3T 1.9MA 0 0 40 20 PTOT MW Transport studies needed to explore electron & ion ITBs, link to performance, scope to raise H factor 2000-2004 data base

7. Hybrid regime sustained for 20s # 68413 (HT3) q95~3.4, 1.4MA/1.5T Pnbi [x10MW] • 20s long hybrid discharges (5 pulses) with q-profile-scan • Record of 186MJ NBI energy bN H89 Flux • 2008 • Assess current drive requirements • Identify the role of core MHD in influencing the profiles Vloop [V] Strike points position ELMs Time [s]

8. Long distance LHCD at high-as required for ITER PNBI (MW) PICRH (MW) PLHCD (MW) ~4.5 sec RC (%) GIM6 13cm -2cm Da ITER-AT • LHCD power up to 3.1MW during ~4.5s (3.4MW coupled at smaller distance) • GIM6 flow 4x1021 el/s D2 • Average RC ~ 4% • Distance LCFS-launcher • ~ 0.15m • Smaller ELMs than in the • previous JET configurations • (compared to 2003 experiments)

9. TF Ripple scan from 0.08  1% No external gas fuelling 4 values of ripple explored with Pabs ~ constant – Fast ion losses up at the highest ripple (~1%) up to 3MW or ~20% Pin Strong density pump out (- 40%) already for dBT~0.5% but higher Te and Ti limited confinement reduction tth (JETTO) reduced by ~ 15% Gas fuelling (not shown here)  density can be increased to ~ no ripple fELM seems to increase with dBT - but ELMs also become irregular - tbd

10. JET Forward programme 2007 - 2010 2007 & 2008 • Installation of ITER-like ICRH Antenna, High Frequency Pellet Injector…. (early April - late October 2007) • Pump-down, commissioning and Restart (late October 2007 – mid February 2008) • Five Experimental Campaigns comprising 166 S/T days (two shift operation), including 73 S/T days for High Level Commissioning of Antenna (under review) (C20 – C25 from mid February to mid November 2008) 2009 & 2010 • Installation of ITER-like Wall, NB Power Upgrade…. (mid November 2008 - mid February 2010 ) • Restart and Experimental Campaigns (mid February to end December 2010)

11. Enhancements to JET Facilities in 2007 Installation of new ITER-like ICRH antennaInstallation of 4 upgraded PINIs in NB system (2.2MW per PINI expected) Heating systems New pellet injector for ELM control and deep fuelling <2mm3; 50-200m/s 10-60Hz <70mm3; 100-500m/s up to 15Hz Fuelling • For studies on: • plasma-wall compatibility • pellet ablation • burning plasma • edge profiles and plasma control Diagnostics To be exploited from 2008

12. EFDA-JET Workprogrammes 2007/8 HEADLINE 1 2007: High level commissioning of new systems and issues that could impact on the design of ITER components 2008: High level commissioning and full exploitation of new systems and issues that could impact on the design of ITER components Not done Good progress Completed • Commission ITER-like ICRH antenna to full performance/reliable operation and begin exploitation • Commission externally matched conjugate T ICRH antenna • Prepare for ITER-like wall project • Commission new high frequency pellet injector and validate it for use for ELM mitigation by pellet pacing • Commission new diagnostics (TAE, magnetics, g−ray detectors) • Address issues impacting on ITER H&CD systems design • Validate ITER burning plasma diagnostics concepts and technologies • Commission ITER-like ICRH antenna to full performance/reliable operation and begin exploitation • Commission externally matched conjugate T ICRH antenna • Prepare for ITER-like wall project • Commission new high frequency pellet injector and validate it for use for ELM mitigation by pellet pacing • Bring new diagnostics to full performance • Address issues impacting on ITER H&CD systems design

13. ITER-like ICRH antenna • Antenna delivered to JET end May 2006 • Fully assembled and tests initiated November 2006 • High power tests completed April 2007 • Tests of matching system ongoing (until ~June 2007) • Installation planned in August 2007

14. Upgraded diagnostic capability • Divertor bolometer • Wide-angle infra-red camera (150oC-2000oC, 18mm,10-0.1ms) • Quartz microbalances in the divertor • New CXRS system with 10ms time resolution • Burning plasma diagnostics(scintillator probe, Faraday cups, time-of-flight neutron spectrometer) • High resolution Thomson scattering Example of power losses observed in main chamber during ELMs and disruptions with new wide-angle infra-red camera

15. EFDA-JET Workprogrammes 2007/8 HEADLINE 2 2007: Preparation of integrated operating scenarios for ITER 2008 Qualification of integrated operating scenarios for ITER Not done Good progress Completed • Develop edge conditions suited to baseline, hybrid and advanced steady-state scenarios that are compatible with ITER-like wall on JET, including integrated benign ELM scenarios • Qualify hybrid scenario as a viable option for ITER • Qualify a robust steady-state non-inductive scenario for application to ITER • Develop highly shaped ELMy H-mode operation to high current (4MA) • Develop edge conditions suited to baseline, hybrid and advanced steady-state scenarios that are compatible with ITER-like wall on JET, including intrinsically benign ELM scenarios and active ELM control • Qualify hybrid scenario as a viable option for ITER • Qualify a robust steady-state non-inductive scenario for application to ITER • Develop highly shaped ELMy H-mode operation to 4MA or higher

16. Internal Transport Barriers with q95~5 and 32MW at ITER-d Pulse characteristics 1.9MA/3.1T Temperature and density profiles 1.9MA/3.1T During ITB Before ITB r/a Time (s) 2006 ITB discharges extended to lower q95~5, higher power (32MW)at Ti~Te, and high core and edge densities with ITER-like shape

17. Hybrid modes at low q95~3 reach bN~3 Pulse No: 67940 1.8MA/1.7T q95~3 Ip (MA) Hybrid 2006 PNBI (MW) PLH (MW) 4xli q95~4 bN Figure of merit qo (MSE) n/nG Hybrid 2003 H-mode 2006 No sawteeth Ha Bootstrap current ~ e.bp Time (s) Hybrid and H-mode in ITER-like shape Characteristics of hybrid discharge at q95= 3.2 H89bN/q952 Maintain q0>1 to avoid sawteeth Hybrid performance similar to H-mode at high q95~4 Hybrid performance at low q95~3, slightly better than H-mode withb controlled in real time

18. Pelin Injector (Tore Supra design) Microwave cavities Main support frame Valves toward roots group Collector LFS, HFS, VHFS tracks Turbo pumps Selectors EFDA-JET Workprogrammes 2007/8 HEADLINE 3 2007: Physics issues essential to the efficient exploitation of ITER 2008: Physics issues essential to the efficient exploitation of ITER Not done Good progress Completed • Impact of toroidal field ripple • Performance limiting instabilities and effect of fast ions • Improve core and edge transport understanding • Determine heat particle and momentum transport properties in plasmas with low external momentum input and ITER-relevant Te/Ti and collisionality • Exploit High Frequency Pellet Injector for particle disposition and transport studies including redial drift and fuelling efficiency • Explore “burning plasma physics” in all ITER-relevant regimes, with the ability to generate significant populations of fast particles (fast~0.5%: fast 4He nuclei with similar population strength to ITER) and a diagnostic capability to probe Alfvén eigenmode stability and measure fast particle redistribution and losses. This programme offers unique opportunities for validating codes in preparation for ITER burning plasma physics.

19. Enhancements to JET Facilities in 2009 ITER-like wall for plasma-wall compatibility studies First wall Modifications to NB sources for increased maximum NB power to: 34MW for 20s or 17MW for 40s (25MW for 10s or 12MW for 20s) Auxiliary power Vertical stabilisation system upgrades for higher resilience against ELMs Plasma control Additional diagnostics for ITER-like wall and improved plasma profiles Diagnostics To be exploited from 2010

20. New ITER-like first wall B&C HFGC 8 1 5 7 3 5a Louvers Louvers 6 4 LBSRP 200μm Plasma sprayed W coating on CFC (Tiles 1-8) High power and ITER-like high triangularity discharges Outer divertor leg on solid W tiles W bulk on Tile 5 (LBSRP) Full W divertor under procurement

21. R&D on bulk W concept • W bulk concept developed under leadership of FZ Juelich • minimises EM forces and optimises mechanical stability • 6mm W-lamellas, poloidal stacks, toroidally isolated 20 MJ Option 1 Toroidally isolated Survived heat flux tests with 7MW for 10s and failure test with 10MW for 14s with temperatures up to 3000oC

22. #70531 PTOT ~ 2.5MW Density Fueling 1.6 1022Ds-1 Divertor Pressure 53 67 Heating & fuelling phase L-mode gas balance in HT3 completed • Completes series of gas balance in high : Type I & III H-modes & L-mode • All C17-C19 data now accurately calibrated during Gas Injection dry runs after end of C19 (to better than 1.2%) • Confirms elevated short term retention between 13-20% • To be compared with ~4% post-mortem campaign average (still too high for ITER!) • Difference due to long term outgassing, thermal release during plasma ops, GDC, disruptions etc HT3 config.8 reproducibledischarges + cryopump regeneration Injected: 1.377 x 1024 D atoms (4.5g)Recovered: 1.208 x 1024 D atoms (3.94g)Retention: 13%

23. First full edge characterisation of ITER-AT plasma (ILW preparation) • Modified ITER-AT for outer strike on LBSRP (bulk W in ILW) • Extensive study of extrinsic seeding to reduce divertor heat loads (frad, injection point, species: Ne, N2, D2) • Seeding appears to provide a degree of ELM moderation • Pedestal degraded at high frad but initial indications that confinement loss can be compensated by weak ITB • No accumulation for Ne or N2 at highest frad (but insufficient time to optimise scenario for ITB) • High bp scenario not yet studied – priority for 2008 – deeper inner divertor may improve ability to mitigate energy load with seeding • Tile calorimetry demonstrates ILW compatible reduction in LBSRP energy load for frad > 40%. • Inner target load only marginally reduced  effect of divetor geometry

24. Maximum power limit 10 s pulse length limit Neutral Beam Power Upgrade 2010 2006 20 s pulse length limit

25. Active ELM control at >30MWwith ITB and neon seeding H=1.5 H≈1 • ELM control with Neon (4-8s) Prad~17MW dithering H-mode • B~3.1T, I~1.9MA, q95~5,PNBI~19.5MW, PICRH~8MW, PLHCD~3.2MW, Wdia~5.6MJ, bN~2

26. JET Programme 2007-2010 DT integrated experiment • ITER-like wall (Be 1st wall, W(C) divertor) • Wall diagnostics • Detritiation techniques Beyond 2010? Confirmation of reduced T-retention • NB Power Upgrade • PF system upgrade • Diagnostics & RTC DT test of fully wall-compatible scenarios JET Programme 2007-2010 ITER-like wall experiment Plasma scenarios in ITER configuration Plasma scenario compatibility • Pellet injector (ELM pacing) • Magnetic perturbation coils (TBD)

27. Conclusions (1/2) 2006 & 2007 • Campaigns C16–C19 (Autumn 2006–Spring 2007) had strong ITER focus, strong European&international participation, very demanding on all systems: • Very limited number of programmes required less than 18MW NB power, and often required high ICRH/LH power • New configurations (e.g. TF ripple) • ITER-like ICRF Antenna, High Frequency Pellet Injector, and additional diagnostic enhancements to be installed in 2007 for exploitation in 2008 • High degree of flexibility will be required to commission Antenna and undertake science programme • Priority elements executed when systems available at full performance • Less demanding elements re-scheduled when full performance not available 2007 & 2008

28. Conclusions (2/2) 2009 & 2010 • ITER-like Wall, NB Power Upgrade and diagnostic enhancements for longer term to be installed in 2009 for exploitation in 2010 • Major challenge will be to accommodate up to 45MW of heating power with beryllium wall and tungsten divertor • JET committed to 27(+5) ITPA High Priority Coordinated Experiments and completed 80% during 2006/7, using 30% of overall run-time • Reports on IEA LTA Tasks 3, 4, 7 and 8 were initiated, coordinated and compiled by EU (see distributed material) IEA LTA & ITPA on JET during 2006/7

29. Topics for which JET committed (1) Topics for which JET committed(red) / 1

30. Topics for which JET committed (2) Topics for which JET committed(red) / 2

31. Topics for which JET committed (3) Topics for which JET committed(red) / 3

33. Topics for which JET did not commit (1) Topics for which JETdid not commit(green, blue)/ 1

34. Topics for which JET did not commit (2) Topics for which JETdid not commit(green, blue)/ 2