laboratorio nacional de fusión f. l. tabarés 15th adas workshop 3-6 oct 2010. armagh. north...

Laboratorio Nacional de Fusión

F. L. Tabarés 15th ADAS Workshop 3-6 Oct 2010. Armagh. North Ireland

Laboratorio Nacional

de Fusión

AMP issues in TJ-II

Francisco L Tabares

Laboratorio Nacional de FusionCIEMAT. Madrid



Outline

- The TJ-II Stellarator. Present status

- Atomic and Molecular Processes of interest- Atomic/molecular beam studies- Li transport modelling- Active Beam CX Spectroscopy- Others- Possible AMP devoted studies



Heliac Stellarator 4 periodsPlasmas ECRH : 600kW,52.6 GHzNBI:500 kW, 40 KeVBT=1 TR=1.5 m<a>= 15-25 cm

Vol Plasma ~ 1m3

P0=5.10-8 mbar

Low Z scenarios :- 2 Graphite Limiters- First Wall Boronization- Full Lithium Coating

Plasmas in TJ-II

Large improvement on Plasma Parameters & Density Control



Supersonic He Beam



DB Not yet complete

Large uncertainties for n=0 electron coupling728 nm affected Triplet relaxation time?Test of self-consistency:

Reconstruction of emission profiles from deduced n, Te values

Other levels?

CX processes?

DB Not yet complete

Large uncertainties for n=0 electron coupling728 nm affected Triplet relaxation time?Test of self-consistency:

Reconstruction of emission profiles from deduced n, Te values

Other levels?

CX processes?



Validation of the CR model

Fig.5.2. Perfiles de ne y Te obtenidos con el diagnóstico del haz de helio a la izquierda. Perfiles radiales de las líneas de helio medidas (con puntos) y simuladas (línea continua) a la derecha. (a) Descarga número 11096; (b) Descarga número 11413.

(b)

0

0.2

0.4

0.6

0.8

1

0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

#11096

I(u.a.)

ρ

667nm

706nm

728nm

0

2 1012

4 1012

6 1012

8 1012

1 1013

0

10

20

30

40

50

60

70

80

0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

#11096

ne

(cm

-3) T

e

( )eV

ρ

0

1 1012

2 1012

3 1012

4 1012

5 1012

6 1012

7 1012

0

20

40

60

80

100

0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

#11413

ne

( -3)cm

Te

( )eV

ρ

0

0.2

0.4

0.6

0.8

1

0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

#11413

( . .)I u a

ρ

667nm

706nm

728nm

(b)

( )a ( )a Thesis A. HidalgoOct. 2006



Ion Temperature (+ plasma rotation) from a He Beam

Only relative vales obtainedOther ion loss processes?A CR model allows for absolute Ti estimates

Fran Guzman, PhD Thesis 2008

Potential Application to other species injected by At. beam: need of Excitation, Ionization data.

F.L. Tabares et al. Rev Sci Instr. 2010, HTPD Proc.



M Goto et al. Phys. Plasmas, Vol. 9, No. 10, October 2002

HeI 667.8 nm HeII 468.6 nm

0

0,2

0,4

0,6

0,8

1

1,2

1,4

0 5 10 15 20

HeI, HeII radial penetration

Intensity

pixel #

He I, 728 nmHe II, 468.6 nm

SOL

- Continuity eq. for He+: He+(r)= He(r).ne.<v>iz/L(r)- Ne, Te (<v>) from He beam-L(r) includes all possible losses for He+

-Deduced values of L(r) too large!!!

-Same discrepancy seen by Nishijima et al in Pisces A He plasmas

L(r) = S(r).I667/I468.(SCR667/SCR

468)



• 1) CH4+e-(H+)

• 2) CH4+e- CH*(a) Ekin

CH (b) Ekin • 3) CH+e-(H+) CH+

• 4) CH+e- CH*

Products (neutral)Products (ion)

+ Proton Reactions + Diss.excitation CH (K4)+K2a

(Behringer JNM1990)

+ Experimental ne,Te profiles

Contribuition of 2 a) negigible

MB studies: HC’s, DC’s, H2,D2

Reaction chain of methane molecules CH4 (Erhardt/ Langer):

CH4+

CH4

CH3+

CH3 CH2 CH C

CH2+ CH+ C+ C2+



Geometric convolution

But: deduced velocities highly sensitive to ne at SOL!!

beam

Large variations of Te(a)

D/H


F.L. Tabarés et al. Alushta 2010 Int. Conference 13-18 Sept. 2010.

Li sputtering yield in TJ-II

11

Deduced value in TJ-II very lowBut: C/B layer deposited previous to lithiation. . Material mixing effect?:. Same Eth H and Li in He plasmas: No Li aloneDetect HLi, BLi, CLi,….

Li=I671.S/XB671

H=IHa.S/XB656

• Exptal Yield Li/H ~2.10-3!!• Theoretic: 3.3.10-2 ( 2/3 ions)

Effect of molecules?


Penetration of Li+ into the plasma

F.L. TabarésSEWG High Z meeting, Liubliana, 1-2 Oct 2009

0

1

2

3

4

5

1040 1060 1080 1100 1120

Li+/Li

L1/LiC8Li8/LiC8Li16/LiC8

BV

time (ms)

Strong penetration during NBI collapse inner

peripheral

Constant Te

Strong penetration of Li into the plasma at Te < 20/30 eV

LiII simulations (L. Mendez et al)

-Low E CX processes?Errea et al. Phys Rev A (2008)

- e- excitation of LiII, LiIII?:S.D.Loch et al. ADNDT( 2006)


Diagnostic Beam CXRS


Standard: Monitoring C VI n= 8 - 7 line (5290.6 A) from CX with H beam (30 keV)

Recently:K,J, McCarthy et al, J. Phys. B 43 (2010) 144020: Fast (28 keV) OV from NBI contamination (H2O)

- Need for cross sections O ions (30 keV)+H+. Test with Ne injection

Plans

- Monitoring of HIBP ions: Cs+, Cs++

- Cross sections Cs++H+, e-, Z+,

- Excitation of Cs++ by e-, H+

NBI Tails

O V


Other studies


Scavenger injection for T control under CFC in ITER(Tabares et al. PPCF 2002)Based on C/N chemistry: Full inhibition of co-deposits in remote areas by ammonia injection

Direct reaction of ammonia with C radicals demonstratedF.L. Tabares et al,Phys Rev Lett 2010Also, ibid IAEA 2010

Characterization of C/N chemistry??NHx, CNH, …

NH3 + CH3 HCN + 2H2+H and NH2 + CH4 HCN + 2H2+H


Li ( Na, Mg?) BEAM DIAGNOSTIC• Thermal Li beam• Detection :

– Interference filter at (671±1) nm– 16 channels PM array

• Movable reference inside the chamber for beam/optics alignment

• Beam allowed into the chamber only during plasma discharge

Detection optics

Oven

Collimator

Alignmentreference

0 1 m

PLASMA

VACUUMCHAMBER

• Oven is heated up to T=590-630 °C• Divergence=1°• Beam size at measurement region =

1.7 cm (FWHM)• <v>=1940 m/s outside the plasma

Thermal Isolator

RESISTANCE

Li

Vacuumvalve

TJ-II portCollimator

5 mm

thermocouple

Controlthermocouple

3 mm

Cucylinder


0 1m

HeTurbopumps

Observationoptics

He beam

pulsed valve & skimmer

ϕ=85,3°

Manometer

PLASMA

VACUUMVESSEL

LASER

Vacuum chamber 1

Vacuum chamber 2

Excimer laser

Dye

laser

Wavelength calibration

Photomultiplier

Oscilloscope

TJ-II Control

He beam +Laser Induced Fluorescence

Test of CR model for He by LIF perturbationA. Hidalgo et al PPCF 2006



Conclusions

AMP of high relevance in TJ-II

Urgent need of AM data : new wall, new diagnostics, new experiments!!

Potential benchmarking of AM data in TJ-II

More collaboration desirable



Thanks for your attention!!

laboratorio nacional de fusión f. l. tabarés 15th adas workshop 3-6 oct 2010. armagh. north...

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