Divertor erosion at ASDEX Upgrade during helium plasma operations

Tomi Vuoriheimo; Antti Hakola; Jari Likonen; Karl Krieger; Martin Balden; Iva Bogdanović Radović; Georgios Provatas; Zdravko Siketić; Karla Ivanković Nizić; Marcin Rasinski; Sebastijan Brezinsek; ASDEX Upgrade Team

doi:10.1016/j.nme.2024.101766

Divertor erosion at ASDEX Upgrade during helium plasma operations

Tomi Vuoriheimo^*, Antti Hakola, Jari Likonen, Karl Krieger, Martin Balden, Iva Bogdanović Radović, Georgios Provatas, Zdravko Siketić, Karla Ivanković Nizić, Marcin Rasinski, Sebastijan Brezinsek, ASDEX Upgrade Team,

^*Corresponding author for this work

BA4511 Fusion energy

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

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Abstract

The effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 10¹⁶ He/cm² were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 10¹⁷ B/cm² and 1.0 × 10¹⁶ D/cm² between the strike points, and significant boron inventories up to 5.9 × 10¹⁶ B/cm² were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.

Original language	English
Article number	101766
Journal	Nuclear Materials and Energy
Volume	41
DOIs	https://doi.org/10.1016/j.nme.2024.101766
Publication status	Published - Dec 2024
MoE publication type	A1 Journal article-refereed

Keywords

ASDEX Upgrade
Erosion
Helium plasma
Marker samples
Material migration

UN SDGs

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

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10.1016/j.nme.2024.101766Licence: CC BY

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title = "Divertor erosion at ASDEX Upgrade during helium plasma operations",

abstract = "The effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 1016 He/cm2 were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 1017 B/cm2 and 1.0 × 1016 D/cm2 between the strike points, and significant boron inventories up to 5.9 × 1016 B/cm2 were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.",

keywords = "ASDEX Upgrade, Erosion, Helium plasma, Marker samples, Material migration",

author = "Tomi Vuoriheimo and Antti Hakola and Jari Likonen and Karl Krieger and Martin Balden and {Bogdanovi{\'c} Radovi{\'c}}, Iva and Georgios Provatas and Zdravko Siketi{\'c} and {Ivankovi{\'c} Nizi{\'c}}, Karla and Marcin Rasinski and Sebastijan Brezinsek and {ASDEX Upgrade Team}",

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year = "2024",

month = dec,

doi = "10.1016/j.nme.2024.101766",

language = "English",

volume = "41",

journal = "Nuclear Materials and Energy",

issn = "2352-1791",

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T1 - Divertor erosion at ASDEX Upgrade during helium plasma operations

AU - Vuoriheimo, Tomi

AU - Hakola, Antti

AU - Likonen, Jari

AU - Krieger, Karl

AU - Balden, Martin

AU - Bogdanović Radović, Iva

AU - Provatas, Georgios

AU - Siketić, Zdravko

AU - Ivanković Nizić, Karla

AU - Rasinski, Marcin

AU - Brezinsek, Sebastijan

AU - ASDEX Upgrade Team

PY - 2024/12

Y1 - 2024/12

N2 - The effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 1016 He/cm2 were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 1017 B/cm2 and 1.0 × 1016 D/cm2 between the strike points, and significant boron inventories up to 5.9 × 1016 B/cm2 were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.

AB - The effect of helium plasma operation on the erosion of plasma-facing components at the low-field side divertor of ASDEX Upgrade was investigated during the 2022 helium experimental campaign. A set of tungsten-covered graphite samples with small platinum marker spots was exposed to both L-mode and H-mode plasma discharges. The highest net erosion of over 1.1 nm/s was observed around the H-mode strike point similar to the case in deuterium plasma. Significant helium inventories of about 6 × 1016 He/cm2 were measured in the scrape-off layer region of the divertor. Impurity deposition including boron and deuterium showed a distinct peak up to 2.4 × 1017 B/cm2 and 1.0 × 1016 D/cm2 between the strike points, and significant boron inventories up to 5.9 × 1016 B/cm2 were also measured on the scrape-off layer side of the H-mode strike point. Platinum re-deposition was not detected between the marker spots, suggesting that it occurs only very locally within the markers. Overall erosion was, as expected, higher than in deuterium discharges, and it also remained comparatively high towards the scrape-off layer, unlike with deuterium.

KW - ASDEX Upgrade

KW - Erosion

KW - Helium plasma

KW - Marker samples

KW - Material migration

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VL - 41

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

M1 - 101766

ER -

Divertor erosion at ASDEX Upgrade during helium plasma operations

Abstract

Keywords

UN SDGs

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