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R. A. Pitts 1 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 JET Task Force E: what we do and how we do it R. A. Pitts on behalf of TF-E 13 November 2006.

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Presentation on theme: "R. A. Pitts 1 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 JET Task Force E: what we do and how we do it R. A. Pitts on behalf of TF-E 13 November 2006."— Presentation transcript:

1 R. A. Pitts 1 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 JET Task Force E: what we do and how we do it R. A. Pitts on behalf of TF-E 13 November 2006

2 R. A. Pitts 2 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 OUTLINE Brief word on EFDA-JET structure Main activities of TF-E –Details in SEWG reports this morning –Experiment Diagnostics specific to TF-E interests –Theory/modelling Current programme –2006 (C16-C17) –Early 2007 (C18-C19)

3 R. A. Pitts 3 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 About 300 different European physicists and collaborators from USA, Japan, Russian Federation, China conduct experiments on JET. A facility collectively used in preparation of ITER Participation of European Physicists in JET early 2006 Experimental Campaigns JET under EFDA

4 R. A. Pitts 4 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Task Force organisation Scientific activities organised into Task Forces: –2 Task Forces for ITER scenarios (S1 and S2) –Topical or Physics Task Forces: M (MHD)Expts. and codes T (Transport)Expts. and codes E (Exhaust)Expts. and codes, strong link to EU-PWI D (Diagnostics)Expts. and diag. developments H (Heating) FT (Technology)Strong link to EU-PWI DT (DT experiments) In addition, a significant ongoing code integration project (led by Vassili Parail) –Since C15-C17 Campaigns, Physics Task Force activities are Channelled by S1 and S2 – experiments organised into S1 weeks and S2 Weeks –Experiments programme always organised around agreed/planned sessions plus 20% contingency, allocated by S1, S2 after discussion with Physics TFLs

5 R. A. Pitts 5 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Programme Elaboration Any particular set of experimental campaigns defined in 3 steps: –1) define the main objectives (EFDA with Task Force Leaders, approved by Committees) –2) details of the programme results from call for scientific proposals sent to all Associations / proposals selected with Task Force Leaders –3) participation in experiments following a call for participation sent to all Associations Step 3 now ongoing for Campaigns C18-C19 in first 3 months of 2007

6 R. A. Pitts 6 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 What does TF-E do? All aspects related to the physics of plasma-wall interaction and SOL/edge transport on JET We have attempted to retain a significant edge modelling effort within the Task Force –Rather than farm out activities elsewhere (e.g. TF-T) –Edge modelling has strong connection to surfaces – i.e. not purely a transport phenomenon –Enormous scope of modelling activity We retain a strong independent contribution to transients (ELMs/disruptions) but strong inter-TF cross-over there (S1, M, S2 …) Gas balance/material migration/erosion/deposition T-retention Growing recent involvement with S2 in the drive to characterise edge/SOL conditions in advanced scenarios –It is becoming inceasingly evident that S1 and S2 are converging in many aspects of scenario development (e.g. Hybrid regime) –SOL of advanced scenario plasmas very poorly diagnosed worldwide, despite obvious importance to magnetic fusion –Lots of room here for involvement of new blood Diagnostic development and upgrade Support EU-PWI-TF and physics preparation for ILW

7 R. A. Pitts 7 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Wall interaction diagnostics Divertor IR Tile thermocouples Langmuir probes Wide angle main chamber and vertical divertor viewing IR (upgrade of vert. system in 2007) Fast reciprocating probes: TTP, RFA

8 R. A. Pitts 8 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Range of visible spectroscopy Plays an important role in studies of impurity evolution, material migration, impurity screening, ELM dynamics

9 R. A. Pitts 9 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Significant upgrade to bolometry system A. Huber et al., SOFT 2006 More viewing chords –Increased sensitivity (lower noise) –Higher time resolution (~2 ms cf. ~20 ms for old system) –Higher quality tomography ELM energy deposition can now be resolved

10 R. A. Pitts 10 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 New DMV system now commissioned K. H. Finken, A. Savchkov et al., FZJ Disruption mitigation valve project now closed (as of 6 th Nov. 2006) – officially handed over to UKAEA Operator –First dedicated experimental session on JET Friday this week! Will investigate effect of Ar as runaway electron mitigator –Initially only Ar, Ne will be allowed –Work underway to allow use of D2/gas mixtures –Helium only in much longer term –Long (~4m) tube length from valve means real time use not possible with heavier gases –Use of D2/different gases in backing volume might make this possible in 2007 Session planned in March 2007 for Tritium recovery by gas termination

11 R. A. Pitts 11 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 # x512 pixels 100 Hz full frame 128x8 subarray at 10 kHz ºC Min. exposure time 20 s –Being used now to study main wall and divertor power loads during ELMs and disruptions Exciting new wide-angle IR system (KL7) ITER-like optical design f ~ 4 FOV 35º E. Gauthier et al., CEA Cadarache

12 R. A. Pitts 12 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Example movies (#67384) Normal frame Difference frame 100 Hz frame-rate, but 300 s snapshot catches an occasional ELM

13 R. A. Pitts 13 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 First wall ELM filament impact Filaments now being seen routinely as campaigns advance Camera generates huge amounts of data – large effort required I p = 2 MA, B = 3T W ELM ~ 150 kJ Two discharges with different contact point of first limiting flux surface #66560, 5.548s P. Andrew, G. Arnoux Coord. Transformation (x,y) (, ) #67384, s

14 R. A. Pitts 14 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 New EP2 Fast Camera project (FC7) C. Hidalgo, J. A. Alonso, CIEMAT Fast Photron APX-RS CMOS camera –3000 fps full frame (1024x1024) –250,000 kHz in sub- array (16 x 128) –down to 1 s exposure –first tests with CIEMAT camera, JET device arrives in 2007 ELM visualisation and PWI (impurity influxes – using filters on selectable wheel) Split view from KL7 periscope (before Cassegrain mirror

15 R. A. Pitts 15 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Also good divertor IR (KL3b) ELM resolved target heat flux (IR) –Type I ELM energy deposition strongly favours INNER target for FWD-B –For REV-B, some evidence for more balanced deposition, –Consistent with similar analysis from AUG (W ELM < 20 kJ) and linked to passage of net current through target plates T. Eich et al., PSI 2006

16 R. A. Pitts 16 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Divertor Langmuir probes S. Jachmich, FZJ Full upgrade of gas box divertor probes (KY4D) During shutdown –New Load Bearing Septum Replacement Plate (LBSRP) now fully equipped –Triple probe capability restored Room for more effort here for interested secondees After C16 and 4 weeks of C17, 62 out of a total of 86 probes still survive

17 R. A. Pitts 17 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Divertor QMBs 5 more QMBs installed following succesful prototype in inner divertor during MarkIIGBSRP campaign. –Only 2 out of 6 now survive only QMB 1 (replacement for original inner divertor QMB) useful for physics studies G. Esser et al., FZJ

18 R. A. Pitts 18 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Vertical Target N2N2 N2N2 P NBI =7.6 MW ELM Type I P NBI =4.7 MW ELM Type III P NBI =7.6 MW ELM Type I Even one QMB teaches us a lot! N2 HT Vertical Target HT HT (sweep) VT Hz/s From TFE contingency session (06/11/2006) HT

19 R. A. Pitts 19 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Edge Modelling within TF-E Significant edge modelling activity within TF-E –Regular edge modelling months during experimental campaigns when large groups of modellers come together on secondment –Last was Feb. 2006, next Feb-March 2007 Activites cover the whole range of edge physics modelling with suite of codes –Main drive in a number of specific areas: SOL flows drifts Code-code benchmarking Erosion redeposition Transients: ELMs/disruptions Turbulence (with TF-T) EDGE2D-NIMBUS EDGE2D-Eirene SOLPS5 (B2.5-Eirene) BIT1 EDGE2D SOLPS5 ERO BIT1 (kinetic) SOLPS5 EDGE2D Analytic ESEL GEM

20 R. A. Pitts 20 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 PIC simulations of ELM losses More realistic description of the ELMy JET SOL using improved PIC simulations (BIT1 code) –Scan in T ped, n ped to vary W ELM –Most of the heat flux arrives with ions on the acoustic timescale –BUT, only ~30% of ELM energy deposited when q target peaks –Electrons account for ~30% of target energy deposition –Strong transient increase over Maxwellian sheath transmission factors during the ELM –Fluid code assumption of fixed underestimates q target at high W ELM Example: T ped = 1.5 keV, n ped = 1.5x10 19 m -3 W ELM ~ 120 kJ, ELM = 200 s D. Tskhakaya

21 R. A. Pitts 21 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Current Programme (C15-C19) Original programme due to start in late 2005 and finish in April 2006 –multiple delays pushed start of campaign (C16) to 25 September after a very short and essentially useless C15 –C16-C17 from 25/09 15/12 –80 total sessions + 20% contingency –spillover from C16-C17 into C18-C19 + additional time granted up to 2007 shutdown for installation of ITER-like ICRH antenna C15-C17 were the subject of call for proposals. C18-C19 has been planned mostly by the Task Forces, without call for proposal –C18-C19 from 08/01 30/03/2007 –89 sessions % contingency –Call for manning sent to Associations on 06/11/2006 TF-E won an allocation of 20 sessions (pure TF-E) from a total of 160 (not incl. contingency) 12.5% proposal –Historically about what we usually hope for

22 R. A. Pitts 22 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 TF-E allocation in C18-C19 TF-E experiments in 2006/07 divide naturally into 3 main programmatic areas: ELMsWall PhysicsDisruptions Small ELM regimes: Convective ELMs Type III ELMs with N2 seeding Material ablation by large ELMs ELM-main wall interaction Gas balance Material migration Local erosion and redeposition Be transport Mitigation Runaway suppression (DMV) 11 sessions 6 sessions 3 sessions Already gained ~2 extra sessions for wall physics through contingency time when beam power failed!

23 R. A. Pitts 23 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 C18-C19 a challenge to TF-E Experiments schedule – TFE heavily involved Pure TF-E Strong TF-E support TF-ripple expts

24 R. A. Pitts 24 5 th EU-PWI TF Meeting Ljubljana, 13/11/2006 Please come and lend a hand (or two)!! Association manning response for 20 November!!!


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