1. FOM-Institute for Plasma Physics Rijnhuizen Association Euratom-FOM T E CT E C T E CT E C Carbon Chemical Erosion Yield Experiments in Pilot-PSI Jeroen Westerhout The Pilot-PSI and Magnum-PSI team: W.A.J. Vijvers, R.S. Al, H.J.N. van Eck, B. de Groot, W.R. Koppers, H.J. van der Meiden, R.J.E. van de Peppel, M.J. van de Pol, P.R. Prins, W.F. van Prooijen, A.E. Shumack, L.W. Veldhuizen, A.W. Kleyn, W.J. Goedheer, N.J. Lopes Cardozo and G.J. van Rooij : R. Engeln, D.C. Schram Forschungszentrum Jülich (TEC): S. Brezinsek

2. 2 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Contents Pilot-PSI Results –Plasma Conditions –Power to Target –Spectroscopy –Profilometry Discussion Conclusions Magnum-PSI

3. 3 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Experimental Setup: Pilot-PSI Source Target B Coils Water cooling To pumps

4. 4 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Experimental Setup: Diagnostics Spectrometer Target Calorimetry from cooling water Thomson Scattering at 17 mm in front of target Window

5. 5 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Plasma Conditions 5 4 3 2 1 0 Electron temperature (eV) Electron density (m -3 ) 10 19 10 20 10 21 10 22 6 Target floating Target grounded 0.4 T 0.8 T 1.2 T 1.6 T 200 A 150 A 100 A

6. 6 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Power to Target n e = 1.2 ± 0.1·10 21 m -3, T e = 2.0 ± 0.2 eV, assume v = 3000 m/s, assume E = E ion + E diss + 3/2 k(T e + T i )) Peak heat flux = 12.6 MW m -2 Integrated profile Flux = 3.7·10 20 s -1 Power = 1.2 kW Power in cooling water 1.8 kW Plasma velocity? Target temperature?

7. 7 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Spectroscopy S/XB from ADAS, D/XB from HYDKIN 422426430434 0 2 4 6 8 Intensity (a.u.) Wavelength (nm) CH H- 0.4 nm

8. 8 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Spectroscopy Ion flux: = n e ·v, assume v = 3000 m/s 01234 0 4 8 12 16 Balmer- flux (a.u.) Ion flux (×10 24 m -2 s -1 )

9. 9 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Profilometry 1.0 slm H 2, 100 A, 0.4 T, target grounded, 100 sec. n e = 0.9 ± 0.1·10 20 m -3, T e = 4.0 ± 0.2 eV Peak heat flux = 1.2 MW m -2 10 mm

10. 10 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Position (mm) Results: Profilometry 10 mm 30 0 -30 Height (µm) 5 10 15 20

11. 11 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Profilometry B10: 2 slm H 2, 120 A, 0.4-1.2 T, varying current to the target (up to 120 A). n e = 9.5 ± 0.5·10 20 m -3, T e = 2.9 ± 0.1 eV Peak heat flux = 11.2 MW m -2 10 mm

12. 12 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Profilometry 10 mm 20 0 -20 -40 Height (µm) 5 10 15 20 Position (mm)

13. 13 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Profilometry Erosion 0.94 mm 3 Deposition 0.47 mm 3 20 0 -20 -40 Height (µm) 5 10 15 20 Position (mm) 50 % > 150 μm

14. 14 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Chemical Erosion Pilot-PSI J. Roth et al., Journal of Nuclear Materials, Vol. 337-339, Iss. 1 (2005), 970-974

15. 15 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Discussion Plasma velocity Flux Target temperature (time dependence) Erosion profiles (anode spots) Rings (colours) Composition of deposited material

16. 16 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Conclusions ITER-like conditions achieved in Pilot-PSI First chemical erosion results are in line with literature Erosion process(es) not fully understood

17. 17 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Magnum-PSI Superconducting magnet

18. 18 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Magnum-PSI Access ITER relevant regime of PSI: 10 24 ions m -2 s -1 in H 2 or D 2 3 T magnetic field 10 cm beam diameter Low plasma temperature < 7 eV 5-10 MW m -2 energy flux density on target Pressure near target 1-10 Pa Total length: 14 m

19. 19 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Future Work Plasma velocities (and neutrals) Target temperature improve cooling Spectroscopy with fiber bundle (chemical erosion profile) Magnum-PSI source development: widening the plasma beam

20. FOM-Institute for Plasma Physics Rijnhuizen Association Euratom-FOM T E CT E C T E CT E C Carbon Chemical Erosion Yield Experiments in Pilot-PSI Jeroen Westerhout The Pilot-PSI team: W.A.J. Vijvers, R.S. Al, B. de Groot, H.J. van der Meiden, R.J.E. van de Peppel, M.J. van de Pol, P.R. Prins, W.F. van Prooijen, A.E. Shumack, L.W. Veldhuizen, A.W. Kleyn, W.J. Goedheer, N.J. Lopes Cardozo and G.J. van Rooij : R. Engeln, D.C. Schram Forschungszentrum Jülich (TEC): S. Brezinsek

21. 21 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Plasma Conditions 5 4 3 2 1 0 Electron Temperature (eV) Electron Density (m -3 ) 10 19 10 20 10 21 10 22 6 Target floating Target grounded 0.4 T 0.8 T 1.2 T 1.6 T 200 A 150 A 100 A A9

22. 22 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Power to Target n e = 0.95 ± 0.05·10 20 m -3, T e = 4.0 ± 0.3 eV, 100 sec. Peak heat flux = 1.2 MW m -2 Integrated profile Flux = 3.3·10 19 s -1 Power = 100 W Power in cooling water 940 W ?

23. 23 T E CT E C Chemical Erosion and Transport Meeting - 23-03-2007 Results: Power to Target 55 A n e = 8.5 ± 0.5·10 20 m -3, T e = 2.3 ± 0.1 eV Flux = 2.8·10 20 s -1 W = 1.4 kW 120 A n e = 10 ± 0.5·10 20 m -3, T e = 2.9 ± 0.1 eV Flux = 3.4·10 20 s -1 W = 2.6 kW 1.8 slm H 2, 200 A, 0.8 T, current to target: