R. A. Pitts 1 5th EU-PWI TF Meeting Ljubljana, 13/11/2006
JET Task Force E:what we doand how we do it
R. A. Pitts on behalf of TF-E
13 November 2006
R. A. Pitts 2 5th 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)
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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
UKAEA17.7%
IST7.1%
IPP6.8%
IPPLM2.1%
HUNG0.3%
HR0.9%
Bulg0.7%
RISO0.9%
BELG3.6%
FZJ6.8% FOM
0.8%
CSU-G1.0%
ENEA16.5%
CRPP4.2%
CZEC1.1%
CEA8.3% CIEMAT
4.1%
MEC1.4%
OAW0.4%
TEKES4.3%
VR11.1%
JET under EFDA
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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 codesT (Transport) Expts. and codesE (Exhaust) Expts. and codes, strong link to EU-PWID (Diagnostics) Expts. and diag. developmentsH (Heating)FT (Technology) Strong link to EU-PWIDT (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 TFL’s
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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
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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
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Wall interaction diagnostics
Divertor IRTile thermocouplesLangmuir probes
Wide angle main chamber and vertical divertor viewing IR(upgrade of vert. system in 2007)
Fast reciprocating probes: TTP, RFA
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Range of visible spectroscopy
Plays an important role in studies of impurity evolution, material migration, impurity screening, ELM dynamics
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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 b e t w e e n E L M s
d u r i n g E L M
R ( m )
R ( m )
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New DMV system now commissioned
K. H. Finken, A. Savchkov et al., FZJ
• Disruption mitigation valve project now closed (as of 6th 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
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#66562 • 640x512 pixels• 100 Hz full frame• 128x8 subarray at
10 kHz• 200 2300ºC• 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
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Example movies (#67384)
Normal frame Difference frame
• 100 Hz frame-rate, but 300 s snapshot catches an occasional ELM
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First wall ELM filament impact • Filaments now being seen routinely as campaigns advance• Camera generates huge amounts of data – large effort required
Ip = 2 MA, B = 3TWELM ~ 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, 26.225s
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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
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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 (WELM < 20 kJ) and linked to passage of net current through target plates
T. Eich et al., PSI 2006
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Divertor Langmuir probes
S. Jachmich, FZJ
• Full upgrade of gas box divertor probes (KY4D) During 2004-05 shutdown– New Load Bearing
Septum Replacement Plate (LBSRP) now fully equipped
– Triple probe capability restored
• Room for more effort here for interested secondeesAfter C16 and 4 weeks of C17, 62 out
of a total of 86 probes still survive
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1
3
4 6
7
8
LBSRP
QM
B 1
,2,3
QMB 4
QM
B 5
QMB 6
Divertor QMB’s
• 5 more QMB’s 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
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Shot
Hz/
s Vertical Target
N2N2
PNBI=7.6 MWELM Type I
PNBI=4.7 MWELM Type III
PNBI=7.6 MWELM Type I
Even one QMB teaches us a lot!
N2
HT
Vertical TargetVertical
Target
HTHT
HT(sweep)
VT
Hz/
s
From TFE contingency session (06/11/2006)
HT
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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 flowsdrifts
Code-code benchmarking
Erosion redeposition
Transients:ELMs/disruptions
Turbulence(with TF-T)
EDGE2D-NIMBUSEDGE2D-Eirene
SOLPS5 (B2.5-Eirene)BIT1
EDGE2DSOLPS5
ERO
BIT1 (kinetic)SOLPS5EDGE2DAnalytic
ESELGEM
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PIC simulations of ELM losses• More realistic description of the
ELMy JET SOL using improved PIC simulations (BIT1 code)– Scan in Tped, nped to vary WELM – Most of the heat flux arrives with
ions on the acoustic timescale– BUT, only ~30% of ELM energy
deposited when qtarget 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 qtarget at high WELM
Example: Tped = 1.5 keV, nped = 1.5x1019m-3
WELM ~ 120 kJ, ELM = 200 s D. Tskhakaya
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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 + 5 + 20% 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
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TF-E allocation in C18-C19• TF-E experiments in 2006/07 divide naturally into 3 main
programmatic areas:
ELMs Wall Physics Disruptions
Small ELM regimes:“Convective” ELMs
Type III ELMs with N2 seeding
Material ablation by large ELMs
ELM-main wall interaction
Gas balanceMaterial migrationLocal erosion and
redepositionBe transport
MitigationRunaway suppression
(DMV)
11 sessions
6 sessions
3 sessions
Already gained ~2 extra sessions for wall physics through contingency time when beam power failed!
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C18-C19 a challenge to TF-EExperiments schedule – TFE heavily involved
Pure TF-E Strong TF-E support
TF
-ripp
le expts
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Please come andlend ahand(or two)!!
Association manning response for 20 November!!!