Laboratorio Nacional de Fusión Asociación EURATOM-CIEMAT PWI activities at CIEMAT (Madrid) presented by F. Tabarés Laboratorio Nacional de Fusión por Confinamiento.

Laboratorio Nacional de FusiónAsociación EURATOM-CIEMAT

PWI activities at CIEMAT (Madrid)PWI activities at CIEMAT (Madrid)

presented by F. Tabaréspresented by F. Tabarés

Laboratorio Nacional de Fusión por Confinamiento Laboratorio Nacional de Fusión por Confinamiento

MagnéticoMagnético

Asociación EURATOM/CIEMAT. Madrid.Spain Asociación EURATOM/CIEMAT. Madrid.Spain

EU-PWITF. Ljubljana 13-15 Nov. 2006EU-PWITF. Ljubljana 13-15 Nov. 2006


OUTLINOUTLINEE-Wall conditioning of TJ-II

-Carbon erosion studies in TJ-II

- Particle transport studies in TJ-II

- Removal/inhibition of carbon co-deposits

-Scavengers: Laboratory studies

JET experiments

-Oxidation, plasma assisted techniques

-Wall conditioning of TJ-II

-Carbon erosion studies in TJ-II

- Particle transport studies in TJ-II

- Removal/inhibition of carbon co-deposits

-Scavengers: Laboratory studies

JET experiments

-Oxidation, plasma assisted techniques


Wall conditioning of TJ-IIWall conditioning of TJ-II

TJ-II Stellerator (R=1.5 m, a <0.23 m, B=1T)Boronisation at beginning of the exp. campaign4 gr o-carborane in He GD B/C ~ 50nmHe (Ne) GD 30 min at beginning of experimental day.ECRH plasmas (up 600 kW): good impurity control (Z~1) and acceptable density control.NBI plasmas (up 400 kW): uncontrolled increase of density

We need a good H2 and O2 getter

Lithium coating

TJ-II Stellerator (R=1.5 m, a <0.23 m, B=1T)Boronisation at beginning of the exp. campaign4 gr o-carborane in He GD B/C ~ 50nmHe (Ne) GD 30 min at beginning of experimental day.ECRH plasmas (up 600 kW): good impurity control (Z~1) and acceptable density control.NBI plasmas (up 400 kW): uncontrolled increase of density

We need a good H2 and O2 getter

Lithium coating


First test of Lithium First test of Lithium coatingcoating

4 Lithium ovens: 2 fixed (side windows) and 2 in retractable

manipulators (top windows)

4 Lithium ovens: 2 fixed (side windows) and 2 in retractable

manipulators (top windows)

1 gr of Li per oven, heated to ~600 ºC during Ne GD1 gr of Li per oven, heated to ~600 ºC during Ne GD

Emission of Li injected froma retractable oven

Emission of Li injected froma retractable oven


First test of Li coatingFirst test of Li coating

Problems:-Lack of good temp. control in the inserted ovens: strong asymmetry of deposited Li.-Accidental venting of TJ-II with N2. Production of Li3N ??

Results: ECRH plasmas (N plasmas?) with a poor density control. Very low H fuelling required

Next campaign: 4 fixed oven.More lab. work in order to improve the coating:Li + He/Ne GD (simultaneous or consecutive)

Problems:-Lack of good temp. control in the inserted ovens: strong asymmetry of deposited Li.-Accidental venting of TJ-II with N2. Production of Li3N ??

Results: ECRH plasmas (N plasmas?) with a poor density control. Very low H fuelling required

Next campaign: 4 fixed oven.More lab. work in order to improve the coating:Li + He/Ne GD (simultaneous or consecutive)


C-film formation and erosion in TJ-IIC-film formation and erosion in TJ-II

CH4 and C2H4 have been injected at the plasma edge using a mobile, instrumented limiter, producing local C-films. Identical (reference ) limiter at 180 º(PSI-2006 to appear J. Nucl. Mat.)

CH4 and C2H4 have been injected at the plasma edge using a mobile, instrumented limiter, producing local C-films. Identical (reference ) limiter at 180 º(PSI-2006 to appear J. Nucl. Mat.)

-C2H4 presents much lower fuelling efficiency than H2

-C2H4 yields only a 15% of H/Hatom compared with H2

-CH/H 3x higher in C2H4 vs CH4

-C2H4 presents much lower fuelling efficiency than H2

-C2H4 yields only a 15% of H/Hatom compared with H2

-CH/H 3x higher in C2H4 vs CH4

-0.2 0 0.2

-0.36

-0.24

-0.12

0

0.12

R-R0 (m)

Z (

m)

CH emission

gass-puff hole

H limiter

-C2H4 injection producedC-layers with high H content(from particle balance)-No difference in erosion between methane/ethylene layers-Physical sputtering dominant

-C2H4 injection producedC-layers with high H content(from particle balance)-No difference in erosion between methane/ethylene layers-Physical sputtering dominant

ResultsResults



Erosion of local C-layersErosion of local C-layers

Comparison of erosion of the deposited films by plasmasfed by limiter puffing or by machine puffingComparison of erosion of the deposited films by plasmasfed by limiter puffing or by machine puffing

Global contamination ofthe full wallGlobal contamination ofthe full wall

Higher erosion by plasmasfeed away for the limiterHigher erosion by plasmasfeed away for the limiter

0

1

2

3

4

5Summary of ethylene injection/erosion

CHC

Inte

ns

ity

(a

.u)

Clean limiterz=-10 Puff z=-10 Plasma z=-15 Puff z=-15Plasma

CHinject.

Reference: z=-10Puff. H2 in cleanlimiter

0

2

4

6

8

10

15280 15285 15290 15295 15300 15305 15310 15315

Inte

nsi

ty (

a.u

)

Shot#

CH/ne

CV/ne


Other studies in TJ-IIOther studies in TJ-II

Transport StudiesImplementation of EIRENE code to the TJ-II geometryBy J. Guasp & A. Salas. Applications:-Simulation of He ECRH plasma using He emission lines of3 different . Neutral profiles obtained. (EPS-2006)-H profile modeling. (E. de la Cal PSI-2006).

DiagnosticsTesting of He C-R model by a supersonic He beam.Sensitivity of model to rate constant uncertaintiesUse of LIF for change population in collisional-coupled levels and estimate the rates of transition with n=0.(A. Hidalgo et al. PPCF 48 (2006) 527.

Transport StudiesImplementation of EIRENE code to the TJ-II geometryBy J. Guasp & A. Salas. Applications:-Simulation of He ECRH plasma using He emission lines of3 different . Neutral profiles obtained. (EPS-2006)-H profile modeling. (E. de la Cal PSI-2006).

DiagnosticsTesting of He C-R model by a supersonic He beam.Sensitivity of model to rate constant uncertaintiesUse of LIF for change population in collisional-coupled levels and estimate the rates of transition with n=0.(A. Hidalgo et al. PPCF 48 (2006) 527.


Modeling of He plasmas by EIRENE in TJ-IIModeling of He plasmas by EIRENE in TJ-II

radii Z(cm) Pixel1 0.614 22.3 12 0.725 23.1 33 0.737 24.3 64 0.840 25.1 85 0.898 26.3 116 0.961 27.1 13

706 nm

728 nm

667 nm

Simultaneous detection by3 arrays of 16 PMTs

-EIRENE neutral code (2) adapted to TJ-II geometry: First case.- 9.6 M trajectories for neutral He followed.- Statistical uncertainty 3% in the He line ratios. - He line ratios insensitive to most of the model parameters.- He line ratios very sensitive to ne and Te edge profiles- Edge profiles adjusted, inside the experimental error limits, for the best fitting.

0

2 1012

4 1012

6 1012

8 1012

1 1013

0 0,2 0,4 0,6 0,8 1

Plasma densityshot #11245

dens

ity (c

m-3

)

r/a

Mofidied

Original

0

200

400

600

800

1 103

1,2 103

0 0,2 0,4 0,6 0,8 1

Plasma Temperatureshot #11245

Tem

pera

ture

(eV)

r/a

Mofidied

Original

The edge profiles from Thomson Scattering and He-beam in H plasmas are a starting point for the simulation

Dotted lines: exp. error limits (20%)Continuous lines: statistical uncertainty of EIRENE (3%)Edge parameters: ne=1.09x1012 cm-3, Te= 41 eV

Good Fitting with smooth edge profiles

Neutral profiles:Absolute calibration of 667 nm He line (error 50%)

Adjust parameters:Ne(a) = 1.09x1012 cm-3 ( 8%)Te(a) = 41 eV ( 4%)Ti(0) = 80 eV ( 24%)Ti(a) = 25 eV ( 10%)He+/He++ = 90% ( 10%)p = 5.6 ms ( 20%)

0

2 1010

4 1010

6 1010

8 1010

1 1011

0 0,2 0,4 0,6 0,8 1

Neutral density Helium

shot #11245, enl = 0.64x1013 cm-3

Perf_He

Expon. Fit1

Expon. Fit2den

s. (

cm-3

)

r/a

Edge= 9.3x1010 cm-3

Rel. Edge/Center = 51

10%

38 %


Validation of the C-R model for He in a supersonic He beam in TJ-IIValidation of the C-R model for He in a supersonic He beam in TJ-II

0

2 1012

4 1012

6 1012

8 1012

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1.2 1013

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40

60

80

100

0.75 0.8 0.85 0.9 0.95 1

#13567

ne

Te

n e(c

m-3 ) Te(eV

)

0

0.5

1

1.5

2

2.5

3

3.5

0.75 0.8 0.85 0.9 0.95 1

#13567

I667expI706expI728exp

I667simulatedI728simulatedI706simulated

I(a.

u.)

0 1m

HeTurbopumps

Observationoptics

He beam

pulsed valve & skimmer

=85,3°

Manometer

PLASMA

VACUUMVESSEL

LASER

Vacuum chamber 1

Vacuum chamber 2

0

200

400

600

800

-0,8 -0,6 -0,4 -0,2 0 0,2 0,4 0,6 0,8

ThomsonECEHaz de He

Te(e

V)

0

200

400

600

800

1000

1200

1400

-1 -0.5 0 0.5 1

13574

Sonda de LangmuirThomsonHaz de He

T e(e

V)

0

2 1012

4 1012

6 1012

8 1012

1 1013

1,2 1013

-1 -0,5 0 0,5 1

#5743

ThomsonreflectómetroHaz de He

n e(cm

-3)

0

2 1012

4 1012

6 1012

8 1012

1 1013

-1 -0.5 0 0.5 1 1.5

#13574

Haz de Li

Haz de HeThomson

n e(cm

-3)

0

2 1012

4 1012

6 1012

8 1012

1 1013

1.2 1013

-1 -0.5 0 0.5 1

#6296

ThomsonreflectómetroHaz He

n e(cm

-3)

0

100

200

300

400

500

600

700

800

-1 -0.5 0 0.5 1

#6296

Haz de HeECEThomson

Te(e

V)

Supersonic He beam diagnostic: Edge profile and Validation of C-R model-a) Comparison with reflectrometry, Li beam and TS--> density profile - b) Comparison with ECE Langmuir probes and TS--> temperture profile-c) Self consistency: reproduction of full emission radial profile

emiss.(nm) 667 706 728


Removal TechniquesRemoval Techniques

Film scavengers: Complete suppression of C-filmdeposition in technical plasmas by addition of some reactive gases: N2, NH3, CNH, SH2, etc…

Suppression of C deposition in CH4/N2/H2 (10:0-10:80)GD(PPCF 44 (2002) L37)

N2 injection on sub-divertor ASDEX-Up: suppression of Cre-deposition (Nucl. Fusion 45 (2005) L27)

N2 sub-divertor injection tested in JET: Nov. 2006

Film scavengers: Complete suppression of C-filmdeposition in technical plasmas by addition of some reactive gases: N2, NH3, CNH, SH2, etc…

Suppression of C deposition in CH4/N2/H2 (10:0-10:80)GD(PPCF 44 (2002) L37)

N2 injection on sub-divertor ASDEX-Up: suppression of Cre-deposition (Nucl. Fusion 45 (2005) L27)

N2 sub-divertor injection tested in JET: Nov. 2006


Mechanism of C-film inhibitionMechanism of C-film inhibition

Cryogenic Trap Assisted Mass Spectrometry (CTAMS)Cryogenic Trap Assisted Mass Spectrometry (CTAMS)

0

0.2

0.4

0.6

0.8

1

100 150 200 250

Vapour Pressures at Low T

P CNHP NH3P H2OP C2H2

P v

ap. (

Pa)

T (K)

1-pumping system 7-diaphragm2-B-A manometer 8-mass spectr.3-Cap. Manometer 9-optic port4-cutting valve 10-manipulator5-gas inlet 11-cryogenic trap6-anode 12-float V measure

1-pumping system 7-diaphragm2-B-A manometer 8-mass spectr.3-Cap. Manometer 9-optic port4-cutting valve 10-manipulator5-gas inlet 11-cryogenic trap6-anode 12-float V measure

Vapor pressure vs. T for different species

Vapor pressure vs. T for different species

J.A. Ferreira et al.PFMC-11. Griefswald 200621 IAEA. Chengdu 2006Submitted: J.Vac.Sci.Tech.Chem Vap. Dep.

J.A. Ferreira et al.PFMC-11. Griefswald 200621 IAEA. Chengdu 2006Submitted: J.Vac.Sci.Tech.Chem Vap. Dep.


CTAMS resultsCTAMS results

CH4/N2/H2 (10:10:80) plasmaCH4/N2/H2 (10:10:80) plasma

N2/H2 (20:80) plasmaN2/H2 (20:80) plasma

condensationcondensation releaserelease

Main product:acetylene

Main product:acetylene

Main product:HCN

Main product:HCN


CTAMS summaryCTAMS summary

Plasma Mixture

Main Products Secondary Products

Characteristic Product Ratios

CH4/N2/H2

10:10:80

Acetylene,

Ethylene,HCN

Acetylene , NH3 C2H2/C2H4=3

HCN/C2=0.1

CH4/Ar/H2

10:10:80

Acetylene, Ethylene Masses 27-29 C2H2/C2H4=1

N2/H2

20:80

HCN ,

Acetylene

C2N2 ,

NH3

HCN/C2H2=4

C2H2/C2H4=1.8

Proposedmechanism:Proposedmechanism:


JET experiments JET experiments ( Nov.06)( Nov.06)

Three scenarios:

- SP low Horizontal+ Type I ELMs,GIM 11, Q<1.2 1022 e/s

- SP low Horizontal-sweep + Lmode ,GIM 11, Q< 6.1021 e/s

- SP low Vertical + Type I ELMs,GIM 11 Q<8 1021 e/s

N2N2


JET experiments JET experiments ctnd’ctnd’

Nitrogen scavenging 30/10/06 late

0

510

15

20

2530

35

40

6824

1

6824

2

6824

3

6824

4

6824

5

6824

6

6824

7

6824

8

6824

9

6825

0

JET pulse #

nor

mal

ized

n

[Hz/

s]

N2 in

Nitrogen scavenging 31/10/06 early

0123456789

10

6825

1

6825

2

6825

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6825

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6825

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6825

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6825

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6825

9

JET pulse #n

orm

aliz

ed

n [H

z/s]

H modeH mode L modeL mode

No significant effect seen with SP at low tile 3 either (H mode)No significant effect seen with SP at low tile 3 either (H mode)

Compatibility of toroidal injection with Type I ELM for required N2 fluxes at JET??? try local injection with AUG fluxes(extrapolated)

Compatibility of toroidal injection with Type I ELM for required N2 fluxes at JET??? try local injection with AUG fluxes(extrapolated)


Removal of a-C:H in gapsRemoval of a-C:H in gaps

Plasma etching in castellatedstructures (1mm wide x3mm deep)

Plasma etching in castellatedstructures (1mm wide x3mm deep)

Etching ratesDeduced by full annealing (TDS) beforeand after plasma exposure:He/O2(20%): 12 nm/minH2/N2(20%): 3.6 nm/minB/C films: much lower rates

Etching ratesDeduced by full annealing (TDS) beforeand after plasma exposure:He/O2(20%): 12 nm/minH2/N2(20%): 3.6 nm/minB/C films: much lower rates

Similar rates if C-coated elements were facing the bottom of the chamber where only a weak plasma was detected (LP)

Similar rates if C-coated elements were facing the bottom of the chamber where only a weak plasma was detected (LP)

Atomic O, surviving after a few collisions with the walls,is the responsible of cleaning.

Atomic O, surviving after a few collisions with the walls,is the responsible of cleaning.

J.A. Ferreira et al. 12-ICFRM. Sta. Barbara. 2005To appear in J. Nucl. Mater.

J.A. Ferreira et al. 12-ICFRM. Sta. Barbara. 2005To appear in J. Nucl. Mater.


C-studies (future-C-studies (future-2007)2007)

CD,CCD,C22, He beam, He beamemission emission (pulsed)(pulsed)

-Chemical sputtering of doped graphite (metal carbides)

(in collaboration C. Garcia-Rosales)

TJ-II NBI Plasma

C dopedC

Methane/He injectionHolder:rotable, radial displacement

Laboratorio Nacional de Fusión Asociación EURATOM-CIEMAT PWI activities at CIEMAT (Madrid) presented by F. Tabarés Laboratorio Nacional de Fusión por Confinamiento.

Documents

suppression of c deposition

tabars laboratorio nacional

plasma n

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complete suppression

validation of c

film deposition

cr model