1. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 1 EU-PWI Task Force & EFDA Plasma Edge Technology Programme Alberto Loarte, Joachim Roth, Volker Philipps

2. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 2 Outline 1.Background to EFDA Plasma Edge Technology Programme and Integration with EU-PWI Task Force 2. Description of Existing Tasks & Status Details to be found in http://efdasql.ipp.mpg.de/efdatpphttp://efdasql.ipp.mpg.de/efdatpp 3. Plans for new Tasks in 2006 4. Discussion of Priorities for 2007 (ELE or post-ELE EFDA ?)

3. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 3 Background Need of fundamental Understanding of PWI Processes Well defined Laboratory Experiments Specific Modelling and Extrapolation to ITER Contributions from Associations without voluntary Physics Programme Financial Volume (2005): 1 M (20% sub.) 5.1.a, 250 k (40% sub.) 5.1b (0.8 M in 5.1.a, 250 k in 5.1b for 2006) EU Task Force aims to better integrate Technology and Physics Aspects of the EFDA Plasma Edge Technology Programme

4. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 4 Integration with EU-PWI TF Topics (I) Tasks in 2002/2003/2004/2005 1. Erosion behaviour Chemical Erosion of C by D/Be, TW2-TPP-ERDEP () (EU-US) Sputtering of W and Be, TW3-TPP-ERTUBE (~ 60% ) SEWG Chemical Erosion of C, TW4-TPP-ERCAR (~ 80% ) SEWG C/W/Be mixed-material formation, TW5-TPP-CARWBER (EU-US) 2. Material transport and re-deposition Flake Formation from Deposits, TW2-TVM-CFC2 () Scavenger Technique, TW3-TPP-SCAVOP () SEWG C x H y Formation and Re-deposition in ITER Geometries, TW4-TPP-TRIDEP Erosion/deposition metal wall + C divertor TW5-TPP-TILCAR Midplane and Divertor W macro-brush studies in ASDEX-Upgrade UT4-TUNAUG & UT5-MBWAUG () Already reported at last years meeting () Reported this year

5. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 5 Integration with EU-PWI TF Topics (II) 3. Fuel recycling, retention and removal (2 SEWGs) Optimisation of He-O Glow for C-H removal, TW5-TPP-HEGLO Characterisation PFC Oxidation Damage, TW5-TPP-TILCAR T removal by non-O 2 oxidative methods, TW4-TPP-TRIREMA-B T retention in ITER-like material mixes and T surf, TW5-TPP-RETMIX 4. Off-normal heat loads (SEWG) Modelling of Disruptions and ELMs, TW3-TPP-DISELM () Validation of ELM Damage Modelling, TW3-MATDAM (~ 30% ) (EU-RF) ELM-Disruption exposed Target Characterisation, TW4-TARCAR (~ 40% ) W and CFC damage and plasma evolution in ITER, TW5-TPP-ITERTRAN Modelling of Be damage under Disruptions/ELMs, TW5-TPP-BEDAM (fut.EU-RF) W and CFC under-threshold damage studies, TW5-TPP-REPELM

6. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 6 Integration with EU-PWI TF Topics (III) 5. Edge modelling, erosion and deposition modelling Improvements to ERO Code and ITER Modelling, TW3-TPP-ERMOD () MD Modelling of Erosion Processes, TW4-TPP-CARWMOD () W Erosion and Edge Plasma Contamination in ITER, TW5-TPP-TUNMOD 6. Edge and SOL physics Improvements to B2-Eirene for ITER Modelling, TW3-TPP-NEUTMOD () Modelling of n-n and n- effects in ITER divertor, TW5-TPP-ITERNEUT 7. Task force relevant diagnostics Speckle Interferometry for Erosion, TW0-T438/01 () Laser Ablation Techniques for Film Deposition, TW3-TPP-ERDIAG ()

7. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 7 Description of Tasks and Status (I) ERTUBE: High T surf erosion of metals (IPP + PISCES-B under EU-US collaboration) R. Doerner + K. Schmid + J. Roth Au High T surf erosion of metals is a general property for low and high Z metals that requires T surf > 0.8 T melt & Fluxes > 10 22 m -2 s -1 & low particle incident energies

8. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 8 Description of Tasks and Status (II) ERTUBE: Composition of redeposits in Be C experiments in PISCES-B (IPP + PISCES-B under EU-US collaboration) Many samples analysed exposed to a range of experimental conditions to determine surface layer structure and composition PSI 2004, M.Baldwin, et al.

9. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 9 Description of Tasks and Status (III) ERCAR: Synergistic effects of C erosion with impurity ions (IPP) Enhanced chemical sputtering by noble gas impurity atoms is confirmed for He, Ne, Ar ion ~ 180 (Ar), 30 (Ne) Enhancement of chemical erosion decreases slightly with atomic mass at low impact energies ITER conditions: Y phys (Ar, Ne) = 0, Y(Ar|D) ~ 0.6,Y(Ne|D) ~ 0.4, R Ar ~ 1000, R Ne ~ 100 C (ion|D)/ C (D) = Y C (ion|D)/(Y chem /R ion ) 0.06 (Ar) 0.4 (Ne) Small effect if Y chem ~ 1% (in agreement with CARWMOD results)

10. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 10 Description of Tasks and Status (IV) SCAVOP : Determination scavenger effect dependence on conditions (IPP) Decrease of deposition with N 2 reproduced but scavenger effect ? Clear formation of volatile molecules (HCN), but also CH 3 and NH 3 increase with N 2 & enhanced N 2 + sputtering of a-C:H layers C 2 H 2 (C 2 H large source of deposits in the experiments) decreases dramatically with N 2 is this the dominant effect ?

11. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 11 Description of Tasks and Status (V) MATDAM + TARCAR: Targets were characterised by FZJ in February and arrived at TRINITI at the end of July (modelling by FZK, analysis FZJ + ENEA-CNR+Frascati) m) (x 10 -2 MJ/m 2 ) Experiments have started already with the plasma gun calibration and low power exposure experiments (~ 0.5 MJ/m 2, 500 s)

12. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 12 Description of Tasks and Status (VI) CARWMOD : MD modelling of W plasma-wall interactions (FZK, TEKES) Emphasis of W compound effects and W blistering FZK Studies of W-O system under D flux TEKES Studies of W-C system under D flux TEKES W blistering under D and He flux Example Result He (@ E inc = 50/100 eV) on W forms bubbles that escape W without causing blister

13. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 13 Description of Tasks and Status (VII) NEUTMOD : n-n effects are not negligible in ITER B2-Eirene has been upgraded to handle these effects (including MAR) (FZJ) for same q pk P DT goes up with n-n col. for same pumped DT S DT goes down (colder gas with n-n col.)

14. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 14 Description of Tasks and Status (VIII) TW0-T438-01 : Erosion diagnostic with speckle interferometry (CEA) Technique tested in ideal realistic conditions produces an ideal resolution of ~10 m 3 method can resolve depths from 2000 m to 50 m with a 10 m resolution Implementation in tokamak requires addressing vibration + large observation area further tests in CEA and (if successful) in Tore-Supra will be pursued Proposed tokamak diagnostic set-up

15. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 15 Description of Tasks and Status (IX) ERDIAG-a : Diagnosis of retention by laser desorption Technique tested in lab conditions with well characterised films Technique demonstrated in TEXTOR with non-optimum laser with good results Diagnostic design for JET approved aiming at demonstration in divertor plasmas

16. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 16 Description of Tasks and Status (X) ERDIAG-b : Diagnosis of retention by LA-OES (or LIBS) Laser Ablation Optical Emission Spectroscopy (CEA) Technique tested in lab conditions with well characterised films Technique demonstrated on TEXTOR tiles Diagnostic incorporated in plans for JET laser ablation system for de-tritiation D/C TEXTOR tile front D/C TEXTOR tile back The critical issue is to optimise crater (depth + profile) to guarantee relevant desorption (by strata)

17. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 17 Plans for new Tasks in 2006 Mixed Materials Studies Study of W/C/O deposits from tokamaks (ASDEX Upgrade, TEXTOR, etc.) with focus on mixed-material formation and T retention Modelling of mixed-material formation processes and T retention Study of W-C-H (+O) system Study of the Be-C-D (+O) system Proof of principle for erosion deposition in-situ diagnostic Ideas ? Demonstration of T-removal techniques for mixed-materials Ideas ? Experimental studies of dynamics of molten layers under transient loads in tokamaks Ideas ? Dedicated ITER PWI modelling ? Ideas ?

18. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 18 Money matters : History and Facts Budget allocated for TPP area of EFDA Technology programme roughly constant since 2003 (20% reduction in 2006 EFDA Technology due to start of ITER construction) Real requested/allocated budget increases with time (in 2005 hopefully by 80-90%) Increase of requested/allocated budget reflects interest of EFDA management on PWI issues + the good work of EU-PWI Task Force!!

19. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 19 Priorities for 2007 Experiments/Modelling on erosion/redeposition in lab experiments and fusion devices Mixed Materials Studies T retention and removal Diagnostics for in-situ T retention measurement Diagnostics for in-situ erosion/redeposition measurements Dedicated PWI modelling in ITER (erosion/redeposition in main Q DT =10 scenario + ramp-up phase) Studies of Be damage under ELMs and disruptions More ideas are very welcome !!!!!

20. Alberto Loarte EU Plasma-Wall Interaction Task Force Meeting – CEA – Cadarache 17 – 10– 2005 20 Conclusions EFDA TPP Technology Programme is well integrated with EU-PWI Research Programme and producing ITER-relevant results As recognised by EFDA and ITER management Two major EFDA Collaborations with US (PISCES-B) and RF (TRINITI) on-going New large collaboration about to be approved with RF (Kurchatov + TRINITI) on Be damage under ITER transient loads EU staff to collaborate in-situ in the experiments (Euratom Mobility) + EU industry to provide targets (+ few Be coated targets?) + destructive analysis of targets to be done in EU labs (new EFDA tasks in 2007) Many Associations involved : CEA, CIEMAT, ENEA-Frascati, ENEA-CNR Milano, FOM-NRG, FZJ, FZK, IPP, IST, ÖAW, TEKES, and VR How to get new Associations involved in Technology Programme ?