K. Krieger, SEWG Meeting on Material Migration and ITER Material Mix, JET, 07.07.2009...

K. Krieger, SEWG Meeting on Material Migration and ITER Material Mix, JET, 07.07.2009

Max-Planck-Institutfür Plasmaphysik

Carbon local transport and redeposition -Results from 13C gas puffing

in the outer divertor of ASDEX Upgrade

K. Krieger, L. Aho-Mantila, M. Airila, A. Hakola, R. Pugno

Association EURATOM Max-Planck Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching, Germany


Outline

Analysis methods

2007 #22573-22585 L-mode D2, -2.5T, 0.8MA

2008 #23646-23654 L-mode H2, 2.5T, -0.8MA

2008 #24183-24189 L-mode D2, -2.5T, 0.8MA

Modelling using B2/EIRENE + ERO


Puff trace amounts of 13CD4 in series of similar discharges and

measure local 13C deposition 2D-distribution at retrieved tiles.

Benchmark data for ERO and for spectroscopic CD flux measurements.

Example: 13CH4 local injection in ASDEX Upgrade


Quantitative analysis of low-Z element deposition

SIMS: Allows to derive depth profilesDifficult to obtain absolute calibration and depth scale

NRA: Allows to derive total amountDifficult to obtain depth profiles

Colorimetry: Allows to derive lateral distribution with high resolutionOnly possible for transparent layers with uniformoptical constantsNo isotope sensitivity


NRA of low-Z elements: D, 10B, 11B, 12C, 13C, 16O


Outline

Analysis methods

2007 #22573-22585 L-mode D2, -2.5T, 0.8MA

2008 #23646-23654 L-mode H2, 2.5T, -0.8MA

2008 #24183-24189 L-mode D2, -2.5T, 0.8MA



Configuration and plasma parameters

11 L-mode discharges

13CH4 puff 1.6−4.6 s

2 Valves


Tiles after exposure

1.5°

1.5°


NRA results

Total injected 13CH4 molecules = 1.2×1020 (upper) = 2.0×1020 (lower)

Total deposited 13C integrated over tiles = 1.1×1020 (upper) = 1.8×1020 (lower)


NRA results

100% local redeposition different toroidal decay lengths upstream/downstream, upper/lower valve downward poloidal shift 40% of injected 13C deposited upstream


Outline

Analysis methods

2007 #22573-22585 L-mode D2, -2.5T, 0.8MA

2008 #23646-23654 L-mode H2, 2.5T, -0.8MA

2008 #24183-24189 L-mode D2, -2.5T, 0.8MA




3 L-mode discharges

13CH4 puff 1.6−4.3 s

2 Valves

Reversed Bt, Ip


Tile after exposure

1.5°

1.5°


NRA results

Total injected 13CH4 molecules = ?

Total deposited 13C integrated over tiles = 1.0×1019

Cancellation / reversal ofdeposition shift atB-field reversal

Shift due to ExB drift


Outline

Analysis methods

2007 #22573-22585 L-mode D2, -2.5T, 0.8MA

2008 #23646-23654 L-mode H2, 2.5T, -0.8MA

2008 #24183-24189 L-mode D2, -2.5T, 0.8MA




4 L-mode discharges (ECRH)

13CH4 puff 1.6−4.3 s

Only upper Valve


Tiles after exposure


NRA results

Total injected 13CH4 molecules = ?

Total deposited 13C integrated over tiles = 0.5×1019


Outline

Analysis methods

2007 #22573-22585 L-mode D2, -2.5T, 0.8MA

2008 #23646-23654 L-mode H2, 2.5T, -0.8MA

2008 #24183-24189 L-mode D2, -2.5T, 0.8MA



Modelling of 2007 results using ERO

B2-EIRENE plasma solutionas background for ERO

ERO runs in a box limitedby the vertical target plate

Impurities exiting box areconsidered lost

L. Aho-Mantila


Modelling of 2007 results using ERO

ERO recreates both E×B drift andupstream deposition due toneutral dissociation products

L. Aho-Mantila


Summary

Data sets available for H-mode, L-mode, L-mode with reversed B-field

Present status: benchmarking 2007 data has made significantprogress

Open questions: sticking coefficients at present only used asfudge parameters. What is the role of surface roughness?(Microscopic deposition asymmetries observed)

Benchmarking the same system with 2008 results.If successful, will it also predict the TEXTOR measurements using theSAME input parameters?

K. Krieger, SEWG Meeting on Material Migration and ITER Material Mix, JET, 07.07.2009...

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