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