Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade

Antti Hakola (Corresponding Author), M. I. Airila, J. Karhunen, M. Groth, A. Herrmann, K. Krieger, T. Kurki-Suonio, G. Meisl, M. Oberkofler, R. Neu, S. Potzel, V. Rohde

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Abstract

We have investigated net and gross erosion of W in the outer strike-point (OSP) region of ASDEX Upgrade with the help of marker probes during low-density/high-temperature L-mode discharges. Post mortem analyses indicate net-erosion rates of 0.04-0.13 nm s-1, with the highest rates measured close to the OSP. Re-deposition was some 30-40% of gross erosion, which is lower than what has earlier been obtained spectroscopically (∼50-60%), possibly due to the special plasma conditions of our experiment and intense flux of W atoms originating from the main chamber. Gross erosion was also estimated by passive emission spectroscopy, and around the OSP the results matched with post mortem data. However, the spectroscopic erosion profile in the poloidal direction was much steeper than the post mortem one. Preliminary ERO simulations have predicted net erosion of the same order of magnitude as experimental results but reproducing the poloidal erosion/re-deposition profiles requires further work.

Original languageEnglish
Article number014026
JournalPhysica Scripta
Volume2016
Issue numberT167
DOIs
Publication statusPublished - 25 Jan 2016
MoE publication typeA1 Journal article-refereed

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Erosion
Gross
erosion
tungsten
profiles
markers
Spectroscopy
Probe
Plasma
chambers
probes
Experimental Results
spectroscopy
Experiment
atoms
Simulation
simulation

Keywords

  • ASDEX Upgrade
  • erosion
  • re-deposition
  • tokamak
  • tungsten

Cite this

Hakola, Antti ; Airila, M. I. ; Karhunen, J. ; Groth, M. ; Herrmann, A. ; Krieger, K. ; Kurki-Suonio, T. ; Meisl, G. ; Oberkofler, M. ; Neu, R. ; Potzel, S. ; Rohde, V. / Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade. In: Physica Scripta. 2016 ; Vol. 2016, No. T167.
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Hakola, A, Airila, MI, Karhunen, J, Groth, M, Herrmann, A, Krieger, K, Kurki-Suonio, T, Meisl, G, Oberkofler, M, Neu, R, Potzel, S & Rohde, V 2016, 'Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade', Physica Scripta, vol. 2016, no. T167, 014026. https://doi.org/10.1088/0031-8949/T167/1/014026

Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade. / Hakola, Antti (Corresponding Author); Airila, M. I.; Karhunen, J.; Groth, M.; Herrmann, A.; Krieger, K.; Kurki-Suonio, T.; Meisl, G.; Oberkofler, M.; Neu, R.; Potzel, S.; Rohde, V.

In: Physica Scripta, Vol. 2016, No. T167, 014026, 25.01.2016.

Research output: Contribution to journalArticleScientificpeer-review

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AU - Hakola, Antti

AU - Airila, M. I.

AU - Karhunen, J.

AU - Groth, M.

AU - Herrmann, A.

AU - Krieger, K.

AU - Kurki-Suonio, T.

AU - Meisl, G.

AU - Oberkofler, M.

AU - Neu, R.

AU - Potzel, S.

AU - Rohde, V.

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N2 - We have investigated net and gross erosion of W in the outer strike-point (OSP) region of ASDEX Upgrade with the help of marker probes during low-density/high-temperature L-mode discharges. Post mortem analyses indicate net-erosion rates of 0.04-0.13 nm s-1, with the highest rates measured close to the OSP. Re-deposition was some 30-40% of gross erosion, which is lower than what has earlier been obtained spectroscopically (∼50-60%), possibly due to the special plasma conditions of our experiment and intense flux of W atoms originating from the main chamber. Gross erosion was also estimated by passive emission spectroscopy, and around the OSP the results matched with post mortem data. However, the spectroscopic erosion profile in the poloidal direction was much steeper than the post mortem one. Preliminary ERO simulations have predicted net erosion of the same order of magnitude as experimental results but reproducing the poloidal erosion/re-deposition profiles requires further work.

AB - We have investigated net and gross erosion of W in the outer strike-point (OSP) region of ASDEX Upgrade with the help of marker probes during low-density/high-temperature L-mode discharges. Post mortem analyses indicate net-erosion rates of 0.04-0.13 nm s-1, with the highest rates measured close to the OSP. Re-deposition was some 30-40% of gross erosion, which is lower than what has earlier been obtained spectroscopically (∼50-60%), possibly due to the special plasma conditions of our experiment and intense flux of W atoms originating from the main chamber. Gross erosion was also estimated by passive emission spectroscopy, and around the OSP the results matched with post mortem data. However, the spectroscopic erosion profile in the poloidal direction was much steeper than the post mortem one. Preliminary ERO simulations have predicted net erosion of the same order of magnitude as experimental results but reproducing the poloidal erosion/re-deposition profiles requires further work.

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