1E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomPlasma Wall Interactions :Tore Supra recent results
E. Tsitrone for Tore Supra team
With special thanks to : M. Bécoulet, C. Brosset, J. Bucalossi, L. Colas, Y. Corre, A. Ekedhal, J. L. Gardarein, P. Ghendrih, C. Grisolia, A. Grosman, J. Gunn, T. Loarer,
P. Monier Garbet, M. Missirlian, R. Mitteau, I. Nanobashvili, B. Pégourié, P. Tamain
Outline :
• SOL physics• C migration / D retention• Heat flux deposition and IR imaging• Prospects
2E. Tsitrone PWI TF meeting 17-19/10/2005
Euratom
SOL Physics
(a tribute to Langmuir probes)
3E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomUnderstanding SOL flows
Particle outflux concentrated on LFS M// towards HFS (M//~0.5 90 % of source on LFS)
Strong flows at the top of the machine : universal feature in tokamaks (JET, TS)
Particle outflux uniform poloidally M//~0
J. Gunn, International conference plasma 2005, 6-9/09/2005, Poland
M// = 1M// = -1
M//~0
M//< 0M//~0
M// = -1 M// = 1
4E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomFrom modelling to experiments …
Plasma ejected from a region around equatorial plane on LFS (narrow poloidal extent ?)
0.0
0.5
1.0
TOPLFS
HFS
BOT
L HF
S /
LT
OT
(a)0.0
0.5
1.0TOP
LFS
HFS
BOT
s//
0 50 100 150
0.0
0.5
1.0 TOP
LFS
HFS X (-1)
BOT X (-1)
(d)
(c)
(b)
M//
DLCFS [ mm ]
0 50 100 150
1017
1018
TOPLFS
HFS
BOT
ne [ m
-3 ]
DLCFS [ mm ]J. Gunn, International conference plasma 2005, 6-9/09/2005, Poland
Influences SOL thickness :• Thin SOL (decay length ~ 3 cm) if this region is obstructed (plasma on LFS)•Thick SOL (decay length up to 20 cm)otherwise (plasma on HFS)
Thin SOLThick SOL
M// to HFS
Reduced M//
M// to LFS
5E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomTurbulent transport in the SOL
Fast acquisition mode on the mobile Langmuir probe (1 s) : signal more bursty in the far SOL
I. Nanobashvili et al, proposal for PSI 2006
3D modelling of the SOL under developpment : transport + turbulence
P. Tamain et al, proposal for PSI 2006
Close to LCFS : pdf ~ gaussian
Far SOL : pdf strongly non gaussian
6E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomELMs suppression by ergodization
DIIID : ELMs suppression w/o confinement degradation over a wide range of pedestal parameters. Easier at low * => good news for ITER
Requirements for “ideal”ergodic coils:
1) As close as possible to plasma (minimize Icoil, )2) Perturbation resonant at the edge but not in
the plasma centre (no NTMs seed islands!)3) Poloidal spectrum sufficiently large to cover
all scenarios (q=3-5: ITB, Hybrid, standard H-mode …)
=> Design of ergodisation coils for ITER underway (EFDA task), to be tested in JET ?
M. Bécoulet et al, EPS 2005
Main difficulties:No space both on JET and ITERExternal coils => far from plasma => large
currents! (~ 200 kA for JET, ~ 400 kA for ITER)
7E. Tsitrone PWI TF meeting 17-19/10/2005
Euratom
C migration / D retention
(the quest for the missing D)
8E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomD retention in TS : overview
Balance on 1 campaign (~ 20 000 s) :
D inventory from particle balance (~ 1023 D)
D recovery :• after shot : ~ 1021 D
(He glow : ~ 1022 D, disruptions : up to ~ 5 1022 D)
D retention rate ~ 1020 D/s (50 % injection, few % recycling flux) depends :
• little of ne, fuelling method• NOT on PICRH
• on PLH (fast e- ? )
D retention rate [Pa.m3/s]
nl = 3.6-4.0 1019m-2
nl = 2.5-2.6 1019m-2
LHCD power [MW]0 1 2 3 4
0.2
0.3
0.4
0.5
0.6
0.7
ICRH =2-4 MW
[J. Bucalossi et al., EPS 2005]
Balance on 1 day : ~ 0 if short pulses (< 30s), >> 0 if long pulses (> 100 s)
>> D inventory from post mortem analysis (~ 1022 D) D balance not closed !
In 2005 long pulse scenario extended to higher power/density :GJA : LH =3 MW , nl = 2.5 3 MW, 6.18 mn, 1.07 GJLH + ICRH =3+4 MW , nl = 3.8 - 5 7 MW, 1 mn, 0.42 GJ
9E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomProgress on carbon balance in TS
Total : 2.7-5.5 g/h
Neutralisers : 1-2 g/hObstacles in SOL : 0.5 g/h
Carbon balance ~ coherent BUT carbon source (~ 1020 C/s ) ~ D retention rate (~ 1020 D/s ) : not sufficient if codeposition only with D/C ratio ~ 1-10 %
TPL
Out. lim + RF ant.
Bumpers
Carbon source : Toroidal Pump Limiter (TPL) Gross erosion from CII spectroscopy : 10 (GJA) to 30 (GJB) g/h
from calculation (GJA) : 41 g/h
E. Dufour et al. EPS 2005
E. Tsitrone et al. IAEA 2004
Net erosion from TPL erosion measurements, averaged over 4 campaigns : 7 g/h (max net erosion rates 2-4 nm/s)from calculation : 5.2 g/h (90% local redeposition)
C. Lowry, private communication
from mass spectrometer : Pumped out : 0.2-2 g/h
C.Brosset, private communication
Carbon sinksfrom analysed samples :
TPL (deposition zones) : 1 g/hC.Brosset et al., PSI 2004, TCM SSO 2005
Other retention mechanisms (bulk diffusion in CFC ?)
10E. Tsitrone PWI TF meeting 17-19/10/2005
Euratom
Heat flux deposition and IR imaging
(High Tsurf = danger ?)
11E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomRF heating generates fast particles
Top / bottom asymmetry : Local : on each waveguide (interaction wave/plasma)Global : E x B drift
Left/right asymmetry : fast ions generated by ICRH (reverses with Ip/Bt)NB : large orbit losses significant in TS (not a pb for ITER)
B, IP
Fast Ions
33894
A. Ekedahl et al, proposal for PSI 2006
e- beams accelerated in LH near field
Convected power
ICRH specific hot spots
ICRH antenna at 60s ICRH: 4MWLH : 3MW
L. Colas et al
12E. Tsitrone PWI TF meeting 17-19/10/2005
Euratom
Heat flux deposition simulation
Interpreting IR imaging
Hot zonesStrong heat flux Low heat flux (C deposits)
Cold zone
Automatic tool for analysis (monitoring C deposits growth ?) and safety applications
IR imaging
Net erosion zones : deposits in gaps
Net redep zones : deposits on tile surface
13E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomInterpreting IR imaging
2D model is necessary for valid deconvolution of IR temperature (to be tested on TS and JET data)
W/m2
Inversion with 1D model
Inversion with 2D model
No negative flux !
JL Gardarein, Y. Corre et al, proposal for PSI 2006
14E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomProspects
PWI program focussed along 4 projects :
• SOL physics (contact person : P. Ghendrih)• C migration / D retention (contact person : E. Tsitrone) • IR imaging (contact person : JM Travère)• Conditionning and detritiation (contact person : C. Grisolia)
TS midterm program workshop + external scientific concil :• SOL transport and turbulence• C material issues : (in)validate C for ITER (C erosion, D retention, detritiation …)
Open for collaboration !
15E. Tsitrone PWI TF meeting 17-19/10/2005
EuratomProspects
• SOL physics More probes to come (RFA, tunnel …) : SOL Ti measurementsSynergy between theory and experiment : can simulations quantitatively explain experimental SOL flows ?
Photo Detector
I ( )0 0 I( ) 0
Light source
L
DParticulate medium
F. Onofri, IUSTI, to be presented in EFDA workshop on dust
• Conditionning and detritiationCharacterization of conditionning (boronisation, glow …)Detritiation : laser implemented on AIA (+ LIBS)Dust : diagnostic (safety)
• IR imaging Implement up to date image processing techniques to IR data (physics + safety)
• C migration / D retention • Extend long pulses to lower Te conditions (high ne / impurity injection)• Solve inconsistency between particle balance / D inventory in TS • Explore bulk diffusion joined TS / PISCES experiment (ITPA) : exposure of CFC samples to high D fluence
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