1. Lithium Sputtering studies in TJ-II Specific 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. TabarésSEWG High Z meeting, Liubliana, 1-2 Oct 2009

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

3. Li sputtering yield in TJ-II Li =I 671.S/XB 671 H =I Ha.S/XB 656 Li / H =I Li /I Ha.(0.2/15) I Li /I Ha (exp)~0.33, Li / H ~2% But: R H ~10%!! So H ~10x., Li/H ~2.10 -3 !! Li/H= S H /1-S ss, S ss = S ss -(1-Rn) Sputt theoretic: 3.3.10 -2 ( 2/3 ions) SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés

4. 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

5. Previous reports a: 0-D model dX/dt= A. H.S H -X/ p -X/ p.S ss =0 x/n e =S H /1-S ss, with S ss = S x -(1-R n ), 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 resultsLab experiments

6. Penetration of Li into the plasma F.L. TabarésSEWG High Z meeting, Liubliana, 1-2 Oct 2009 inner peripheral Constant Te Strong penetration of Li into the plasma at Te < 20/30 eV

7. Layer (B/Li) mixing effects Li sputtering yield lower by ~2 after He GDC SEWG High Z meeting, Liubliana, 1-2 Oct 2009F.L. Tabarés Before GD After GD

8. Boron layer on top of Li F.L. TabarésSEWG High Z meeting, Liubliana, 1-2 Oct 2009 Much lower yields - E bonding ?? But good recycling!! -Role of bulk vs surface Li

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

10. Summary of Results F.L. TabarésSEWG High Z meeting, Liubliana, 1-2 Oct 2009

11. 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