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1 ITPA - DSOL - TorontoS. Brezinsek TEC Hydrocarbon spectroscopy on EU tokamaks S. Brezinsek on behalf of the EU task force for Plasma-Wall Interaction.

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Presentation on theme: "1 ITPA - DSOL - TorontoS. Brezinsek TEC Hydrocarbon spectroscopy on EU tokamaks S. Brezinsek on behalf of the EU task force for Plasma-Wall Interaction."— Presentation transcript:

1 1 ITPA - DSOL - TorontoS. Brezinsek TEC Hydrocarbon spectroscopy on EU tokamaks S. Brezinsek on behalf of the EU task force for Plasma-Wall Interaction presented by V. Phillips TEXTOR: Photon efficiencies for different types of hydrocarbons in ionising plasmas HYDKIN:Measured and calculated photon efficiencies in different devices AUG: Chemical erosion and photon efficiencies under detached plasma conditions JET: Chemical erosion yielded in higher hydrocarbons TF-E

2 2 ITPA - DSOL - TorontoS. Brezinsek TEC TEXTOR– Photon Efficiencies for Hydrocarbons: CD 4 Aim: Measure D/XB values without contamination from deposited and re-eroded hydrocarbons. Comparison with HYDKIN and ERO calculations D/XB Exp. =36 D/XB HYDKIN =46 D/XB ERO =32 CD A-X band (CD from CD 4 )

3 3 ITPA - DSOL - TorontoS. Brezinsek TEC C x H y in D plasmas: T e =35 eV, n e =2.2*10 18 m -3 at the emission location C x D y in H plasmas: T e =45 eV, n e =1.8*10 18 m -3 at the emission location CH A-X band (Gerö band) C 2 d-a band (Swan band) Brezinsek et al. PSI 2006 TEXTOR: Effective Photon Efficiencies for C x H y, C x D y

4 4 ITPA - DSOL - TorontoS. Brezinsek TEC TEXTOR: CD + Observed in Hot Edge Plasmas TEXTOR benchmark experiment with CD 4 :  20 % of theoretically expected CI nm per C observed  50 % of theoretically expected CII at nm per C+ observed  20 % of theoretically expected D  per H observed => CD + identified in TEXTOR plasmas => break-up via molecular ions important

5 5 ITPA - DSOL - TorontoS. Brezinsek TEC Part of the dissociation chain (CH 4 ): CH 4 + CH 4 CH 3 + CH 3 CH 2 CHC CH 2 + CH + C+C+ C 2+ Reaction kinetic analysis with HYDKIN (Reiter 2006) for CH 4 T e =45 eV CH + CH HYDKIN: CH + vs. CH in the Hydrocarbon chain T e =5 eV CH CH + Hot limiter plasma (TEXTOR)Cold divertor plasma (AUG, JET)

6 6 ITPA - DSOL - TorontoS. Brezinsek TEC HYDKIN: Effective Photon Efficiencies for Methane Comparison of measured effective photon efficiencies with HYDKIN calculations (const. plasma, no deposition, no transport) Janev-Reiter database is reliable in the range between 5 eV and 100 eV Detailed comparison with the aid of erosion and deposition models necessary Brezinsek et al. PSI 2006

7 7 ITPA - DSOL - TorontoS. Brezinsek TEC AUG: Hydrocarbon Injection in Detached Plasmas L-mode discharges with outer divertor detachment Injection of CH 4 and C 2 H 4 in the SOL, Separatrix and PFR in the volume: T e =1.2 eV, n e =3*10 20 m -3 at the target (separatrix): T e =2.3 eV, n e =4*10 18 m -3

8 8 ITPA - DSOL - TorontoS. Brezinsek TEC Brezinsek et al. PFCM 2006 AUG: Photon Efficiencies in Detached Plasmas Intrinsic CD A-X spectrum --- attached plasma --- Intrinsic CD A-X spectrum with strong BD contamination --- detached plasma --- CH A-X spectrum from injection and CD A-X intrinsic background --- detached plasma --- CH A-X spectrum from injection and CD A-X intrinsic background --- attached plasma ---

9 9 ITPA - DSOL - TorontoS. Brezinsek TEC AUG: Erosion Yields in Detached Plasmas Decrease of CH and C 2 light much stronger than increase of D/XB => Significant decrease of the hydrocarbon flux in detachment D/XB for CH from CH 4 : 18+-/7 D/XB for CH from C 2 H 4 : 47 +/-19 D/XB for C 2 fromC 2 H 4 : 407 +/-134 Measured D/XB values are higher than in attached plasmas and higher than predictions with HYDKIN! Y chem =3.2*10 -2 (ion flux only) Y chem =2.9*10 -3 (atom and ion flux) Erosion yield at the separatrix for detached conditions: Reduced influx is largely compensated by lower plasma outflux. => Consideration of neutral outflux to the target is important! Erosion yield in line with Roth-formula: Y chem =2.5*10 -3 (atom and ion flux)

10 10 ITPA - DSOL - TorontoS. Brezinsek TEC Circumferential injection into the attached outer divertor: i) Discharge with C 2 H 4 injection ii) Discharge with H 2 injection Nearly identical local plasma conditions Assumption: symmetric and homogenous injection Brezinsek et al. EPS 2005 JET: C x H y Contribution to the Erosion Yield

11 11 ITPA - DSOL - TorontoS. Brezinsek TEC JET: C x H y Contribution to the Erosion Yield Most reliable value for Y chem is achieved when the strike point is at GIM10 Toroidal inhomogeneity of gas injection module included (=> information from tracer experiments) Bypass in the outer divertor considered!  Photon efficiencies and erosion yield lowered in comparison to first analysis (EPS 2005) D/XB for C 2 Swan band from C 2 H 4 about 75 Y chem associated to higher hydrocarbons about 0.6% Brezinsek et al. PSI 2006

12 12 ITPA - DSOL - TorontoS. Brezinsek TEC Summary TEXTOR: - Photon efficiencies for different hydrocarbons - Information about hydrocarbon catabolism - Detection of CH + in the hot edge plasma AUG: - Photon efficiencies for CH in detached plasma conditions - Hydrocarbon particle flux reduction in detached plasmas - Neutral flux to the target important for yield determination JET: - Circumferential injection in the outer divertor - Erosion which yielded in C 2 H y lower than previously deduced HYDKIN: - Janev & Reiter data base reliable for ionising conditions - Normalised D/XB values deduced in different machines and compared with HYDKIN

13 13 ITPA - DSOL - TorontoS. Brezinsek TEC Plasma parameters inner and outer JET divertor

14 14 ITPA - DSOL - TorontoS. Brezinsek TEC AUG: Plasma Parameters at the Target


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