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

Antti Hakola; Markus I. Airila; J. Karhunen; M. Groth; A. Herrmann; K. Krieger; T. Kurki-Suonio; G. Meisl; M. Oberkofler; R. Neu; S. Potzel; V. Rohde; ASDEX Upgrade Team

doi:10.1088/0031-8949/T167/1/014026

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

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

Research output: Contribution to journal › Article › Scientific › peer-review

19 Citations (Scopus)

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 language	English
Article number	014026
Journal	Physica Scripta
Volume	2016
Issue number	T167
DOIs	https://doi.org/10.1088/0031-8949/T167/1/014026
Publication status	Published - 25 Jan 2016
MoE publication type	A1 Journal article-refereed

Keywords

ASDEX Upgrade
erosion
re-deposition
tokamak
tungsten

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1088/0031-8949/T167/1/014026

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title = "Gross and net erosion of tungsten in the outer strike-point region of ASDEX Upgrade",

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.",

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AU - Hakola, Antti

AU - Airila, Markus 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.

AU - ASDEX Upgrade Team

PY - 2016/1/25

Y1 - 2016/1/25

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.

KW - ASDEX Upgrade

KW - erosion

KW - re-deposition

KW - tokamak

KW - tungsten

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JF - Physica Scripta

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ER -

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

Abstract

Keywords

UN SDGs

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