6 th ITPA-SOL/Divertor 会议情况介绍

1. 6th ITPA-SOL/Divertor 会议情况介绍 胡建生 10 July, 2005

2. July 4-7, 2005 • Facultat de Ciències Jurídiques de la Universitat Rovira i Virgili • Tarragona, Spain

3. Main sessions in this meeting • D/T inventories (surfaces and sides of tiles) & removal • Dust • High-Z experience • Mixed materials effects • First wall loadings & joint meeting with MHD • Experiment/Modelling of plasma detachment, divertor neutral dynamics and divertor geometry effects. • Experiment/Modelling of scrape-off layer flows. • Estimate of the effects of Be operation in ITER • ITER dome

4. D/T inventories (surfaces and sides of tiles) & removal • Co-deposition • Recent results on carbon deposition and fuel retention in gaps. • Analysis of C-Mod tiles for B/D co-deposition on tile sides. • Recent results on carbon migration and deposition in AUG. • 13C injection at the outer divertor in JET. • D/T removal • Recent activities on photo-cleaning in EU. • Oxygen cleaning activities in TEXTOR. • Oxidation wall conditioning in HT-7. • ICRF H/D removal in LHD. • N2 seeding experiments in AUG. • D/T inventories • Long pulse operation and related wall saturation effects.

5. Dust • Modeling • Modeling of dust dynamics and transport in ITER with the code DUSTT. • Modelling of dust formation in plasmas • Modelling of dust dynamics • Experiment • T-10 results • JT-60 & LHD results. • Detection of dust particles on remote surfaces. • DIII-D results • Enormous quantities of dust in C-Mod and the effects

6. High-Z experience • ASDEX Upgrade W operation • High temperature erosion and melting of W in TEXTOR • Removal of B from C-Mod and effect of boronization • W-tile experience from JT-60U and laboratories • Conclusions about the use of high-Z materials

7. Mixed materials effects • IPP results on alloy formation of Be and W • PISCES Be/C mixed materials studies • Studies of mixed material erosion/deposition at the Garching dual beam experiment

8. First wall loadings & joint meeting with MHD • EU-PWI disruption wall loadings • JT-60U disruption mitigation • C-Mod & DIII-D status of disruption mitigation work • AUG disruption mitigation • JET disruption mitigation • Discussion of first wall loading database • JET ELM measurements/modeling • AUG, DIII-D & MAST measurements of wall fluxes • JT-60U ELM fluxes to walls • Analysis of intermittent transport in JT-60U • Discussion of ELM and disruption wall fluxes

9. Estimate of the effects of Be operation in ITER • several Be-wall erosion duringsteady-state and transient plasma conditions including its spatial distribution • several Main wall eroded Be migration to the divertor and C/W migration onto the Be wall in ITER • several Implications of a Be wall on T retention and removal in ITER (including mixed material formation • several Operability of ITER with a Be main wall/limiter including effect of PFCs damage due to tranients • Plans and status of Be wall experiment in JET.

10. ITER dome • ITER presentation on original strategy for the dome and why to remove it • ITER calculations of divertor performance with & without dome • Extrapolation of a diffusive neutral solution to ITER • Discussion of how to make progress

11. Proposal for joint research • Scaling of Type I ELM energy losses. • Hydrocarbon injection to quantify chemical erosion. • Scaling of radial transport. • Comparsion of disruption energy balance in similar discharges (and disruption heat flux profiles). • Role of Lyman absorption in the divertor. • SOL flows and influence on impurity shielding. • Study on separatrix density and edge density profiles. • Radial ELM propagation • C13 injection experiments to understand C migration. • Modelling of different gases effects on disruption mitigation power deposition (and disruption mitigation experiments on JET and C-mod) • Oxygen wall cleaning. • Carbon deposition measurements in tile gaps. • ICRH wall conditioning.

12. Next meeting • China • Japan

13. D/T removal • Oxidation wall conditioning in HT-7. • Focus topics • Removal rate of C, H/D; • The influence of parameters; • Oxygen retention; • How to remove oxygen; • Recovery of plasma; • Prediction for ITER; • The physics of oxidation; • The removal of co-deposition. • Suitable methods and Good results • Question: • The location removal; • Recent activities on photo-cleaning in EU. • Good results; • Questions: • how to control the bulk erosion of carbon during removal; • Is it a in situ techniques; • Oxygen cleaning activities in TEXTOR. • O-ventilation; O-GDC and O-ICR(only one parameters) • Only discussed • the partial pressure; • removal rate of C, H/D; • Removal of deposited film • Questions: no water formation observed;

14. Questions for fuel removal The possibility of adopting in ITER is still uncertain. • Wall material in ITER? • Plasma recovery? What heating method is most promising? How to remove dust? How much can we use plasma heating to reduced T/Be, C fraction on PFC sides? Oxygen: Possible in an Be dominated enviroment, such as for C-removal at remote access? C-Oxidation also possible in C-layers with same B? How can we remove fuel from Be-rich layers with some C? Wall saturation and density control is a real issue for ITER? Removal rates and applicably to various material and hidden areas?

15. Dust discussion • What is the role of dust in: • Core contamination • Impact on plasma transport • T retention and transport • PFM transport, erosion, Re-deposition • Physics issues: • Dust formation(where, when and how) • Dust dynamics in tokamak plasma(forces, erosion/growth, etc) • Dust interactions with surface; • ?

16. Discussion of High-Z experiment • Would we dare to built a full tungsten burning device; • As early as ITER in T phase • Restriction in operation • Fuel retention

17. Discussion of mixed material session • Be-W system • Potential for major malfunction. • Must Be discussed under the most likely ITER scenario. • Be-C system • Be reduced chemical erosion of C; • What is inflence on T retention? Similar co-deposition at 300K, but release at lower temperature • W-C system • W erosion enhanced by C impurities. • W eroded by C ions, C removed by D ions.

18. Discussion of Boronization • Boronization in case of a Be-free device? • What is the effect of boronization? • We do not realy know? • How long does last? • Other techniques of wall conditioning? • Just for oxygen reduction? • Operation with full W without wall conditioning?

19. First wall load discussion • Disruption power loads on first wall • Physics guidelines for disruption thermal loads • Need recommendation to CC • How do we resolve the big variability between machines? • Is this different physics, diagnostic difference, difference of definition? • On one machine for one type disruption? • Vapour shielding impact? • First wall or divertor where do do need guidelines? • Loads at non active divertor? • Do we have any information on first wall loads at all?

20. Disruption mitigation • Do we need it at all? • Mitigation pros and cons is really to login? • What is the quality of disruption predication to go with it? • Depend on disruption type? • Possibly of increased eddy force even if low halo forces? • Is mitigation suitable for e.g. at scenarios? • Is Q=2 surface reachable in ITER? • Disruption mitigation scenarios and guidelines for the design of mitigation system-need recommendation.

21. ELM power loads on first wall • Impact of hot ions on high-Z wall. • Still issues of how for MHD radial pertardation • Does filament model mean well flux only on limiter? • Does it fell as anything about the limiter design? • Over what area is the energy deposited? • What’s the impact of rotation.

22. Erosion/deposition in HT-7-in 32th EPS meeting • 总共有14人感兴趣; • 同样的现象在很多装置都已经发现: • 表面沉积与腐蚀分布; • 极向限制器边上及内衬上的Flake; • 多人表示要用我们的图片做分析,了解其生长过程; • Dust; • Thick film; • 将HT-7结果收集在DATA BASE内; • For ITER

23. 总体印象 • 安排紧凑; • 主题明确; • 讨论激烈.