lithium sputtering studies in tj-ii specific diagnostics: -li emission at 671nm at the edge rel....
TRANSCRIPT
Lithium Sputtering studies in TJ-IISpecific diagnostics:- Li emission at 671nm at the edge Rel. Calibrated in situ- 6 H monitors- Array of Li+ emmision at the edge: r/a: 1.05 to 0.75- Edge ECE (ECRH plasmas)- Supersonic He beam for ne and Te at the edge- NPA for CX Ti determination
- ECRH and NBI plasmas: up to 800 kW heating power- H and He plasmas- Li/B and B/Li coatings
+ Laboratory experiments ( sputtering and recycling)
F.L. Tabarés SEWG High Z meeting, Liubliana, 1-2 Oct 2009
Example
F.L. Tabarés SEWG High Z meeting, Liubliana, 1-2 Oct 2009
0
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0,8 0,85 0,9 0,95 1
Te edge He beam
Te1(1046.270020)Te2(1062.900024)Te3(1079.569946)Te4(1096.229980)Te5(1112.900024)Te6(1129.550049)Te8(1162.890015)Te7(1146.229980)
Te eV
r/a
0
1
2
3
4
5
1000 1050 1100 1150 1200
Li sputt-22180
Li 671 nmHa C4Ha limiter A3Ha limiter C3Ha D4CV
Intensity
t ms
NBIECRH
Li sputtering yield in TJ-II
Li=I671.S/XB671
H=IHa.S/XB656
Li/ H =ILi/IHa.(0.2/15)
• ILi/IHa(exp)~0.33, Li/ H ~2%
• But: RH~10%!!
• So H~10x. ,
• Li/H ~2.10-3!!
• Li/H= SH/1-S’ss, S’ss= Sss-(1-Rn)
• Sputt theoretic: 3.3.10-2 ( 2/3 ions)
SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés
Results
Sputtering yiled 4-6 times lower than expected:
- E ions?- Li+ screening?
Strong Te dependence!!!
Larger bonding E ?
GDC: mixing??
SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés
0
1
2
3
4
0 20 40 60 80 100
Li sputt vs Te Li/H
/Li H
( )Te eV
Previous reports
a: 0-D model
• dX/dt= A.H.SH-X/p-X/p.Sss=0
x/ne=SH/1-Sss, with Sss= Sx-(1-Rn),
Rn=self-reflexion coeff, SH, Sss dep on E and angle of incidence
Li examples
SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés
DIII-D results Lab experiments
Penetration of Li into the plasma
F.L. Tabarés SEWG High Z meeting, Liubliana, 1-2 Oct 2009
0
1
2
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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
Layer (B/Li) mixing effects
0
2
4
6
8
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1000 1050 1100 1150 1200
Li sputt-22105-22172 15:33:29 3/6/09
LITIO_C8-22109LITIO_C8-22122LITIO_C8-22130LITIO_C8-22145
LITIO_C8-22105
time (ms)
0
0,5
1
1,5
2
2,5
3
3,5
1000 1050 1100 1150 1200
Li sputt-22105-22172
HALFAC4-22109HALFAC4-22122HALFAC4-22130HALFAC4-22145
HALFAC4-22109
time (ms)
Li sputtering yield lower by ~2 after He GDC
SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés
Before GD
After GD
Boron layer on top of Li
F.L. Tabarés SEWG High Z meeting, Liubliana, 1-2 Oct 2009
0
0,1
0,2
0,3
0,4
0,5
0 10 20 30 40 50 60 70 80
Li/Ha
Li/H
( )Te eV
Sputt B on Li
Much lower yields
- E bonding ??
But good recycling!!
-Role of bulk vs surface Li
Laboratory Experiments
F.L. Tabarés SEWG High Z meeting, Liubliana, 1-2 Oct 2009
Summary of Results
F.L. Tabarés SEWG High Z meeting, Liubliana, 1-2 Oct 2009
Plans
• Ver evolución de sputtering sin mezcla de B/C/Li• Deposition samples…Análisis post mortem (B5 top)• Efecto de más Li en plasma
• Modeling Li+…transporte del Li en el borde
SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés