EMC3-Eirene simulations of the tungsten injection experiments in Tore Supra

1. EMC3-Eirene simulations of the tungsten injection experiments in Tore Supra T.Lunt, M.Kočan, Y.Feng, J.Gunn, O.Meyer PSI 2012 Aachen Outline + Introduction / Motivation + EMC3-Eirene + Simulation of the Tore Supra Deuterium bulk plasma + W transport study + Summary

2. Introduction / Motivation Tungsten in magneticaly confined fusion plasmas TS WEST Bucalossi F.E.D. 2011

3. Introduction / Motivation 3D simulations of the Tore Supra edge plasma LFS limiter ICRH Q5 ICRH Q2 Lower hybrid C2 HFS limiters Probe: ~ 4 cm diameter non-perturbing diagnostics or limiter? ICRH Q1 Lower hybrid C3 Toroidal Pump Limiter Electrical probes are used world wide in tokamak SOLs

4. The Edge Monte Carlo 3D – Eirene (EMC3-Eirene) code package

5. EMC3-Eirene Braginskii‘s & Kinetic equations EMC3 (plasma) Features: + plasma fluid equations solved by Monte Carlo technique + full 3D geometry + classical parallel transport + anomalous perpendicular transport Limitations: + no drifts + no flux limiters + spatially constant perpendicular transport coefficients + volumetric recombination not included Eirene (neutrals)

6. Simulation of a the Tore Supra Deuterium bulk plasma

7. Simulation of the TS D bulk plasma Simulated configurations HFS LFS probe TPL

8. Simulation of the TS D bulk plasma Radial profiles (A) (B) (C) Virtual probe TS: Zagorski R. PPCF 2006 JET: Matthews G.F. JNM 2005

9. Simulation of the TS D bulk plasma Configuration B M Virtual Mach probe +1 0 -1 Perturbed volume length: 0.5csDx2/D=70 m~Lc Hutchinson‘s formula: M=0.4 ln(jup/jdown) ICRH Q2 LFS limiter

10. Simulation of the TS D bulk plasma Radial profiles (A) (B) (C) (A‘) Virtual probe Open questions: + does self consistent solution exist? + effect of the B-field ripple? + accuracy of equilibrium? + effect of B x grad |B| drift + fluid approach valid?

11. W transport study

12. W transport study Injection of tungsten hexacarbonyle W(CO)6 W(CO)6 container extension spring Movement of the probe mass cylinder valve gas exhaust pair of LP pins W + C + O Gas cloud Kočan M. 2012 submitted to RSI

13. W transport study Core VUV spectroscopy and bolometry during injections 53 W injections @ DrLCFS = 20..90 mm in 11 plasma pulses t [s] O.Meyer P1-065

14. W transport study EMC3-Eirene simulations of the W transport nW 5x1016m-3 injection of FW=6.25x1018 s-1 0 LH C2 LH C3 LPT ICRH Q1

15. W transport study Comparision between experiment and simulation 0D model for the core W content: Screening factor: Experimental mean residence time: Mean residence time simulation:

16. W transport study Comparision between experiment and simulation Dz=D

17. Summary + The full 3D bulk plasma, neutral gas and W impurity transport was computed for the first time in Tore Supra (TS). + Three configurations were investigated the (A)high field side-, (B) bottom- and (C) low field side limited cases. + In particular case (B) showed a strong discrepancy with Mach probe measurements in the upper part of the machine previously observed at TS and JET. + A ‚virtual probe‘ was found to disturb the TS SOL strongly, questioning the locality of the measurement. From the particle fluxes on the two sides the probe we deduced Mach numbers between the unperturbed and experimental ones. + The W transport simulation showed a rather weak dependency on the configuration and a moderate dependency on DZ. + The simulated and measured mean residence times for W show a similar tendency, the absolute value, however, differs by a factor of about 10.