Surface composition and morphology changes of JET tiles under plasma interactions

JET-EFDA collaborators

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)

Abstract

Plasma interactions with the main chamber of magnetic fusion devices result in net erosion from some areas and net deposition at other locations. However, high energy particle irradiation means that there are continuous erosion and re-deposition processes involved, creating new surface structures. Although the net deposition can be readily assessed, net erosion and material mixing is difficult to determine. In 2005 marker tiles were mounted in the JET vessel which have a thin tungsten (W) layer deposited on the CFC substrate with a ∼10 μm carbon layer on top. This layered structure was designed to determine the areas where some erosion had occurred during JET plasma operations, when the tiles were removed for analysis in 2007.

This paper describes the results from a set of tiles mounted in a poloidal limiter (in Octant 8) at the outer wall of the main chamber; a comparison is made between the data from tiles near the top, middle and bottom of the limiter. A set of ion beam techniques together with electron microscopy were used to provide a detailed analysis of the tiles. In general, since plasma interaction is strongest near the centre of the limiter where the tile is closest to the boundary of the confined plasma, erosion dominated on the central tiles, with deposition further from the plasma boundary. Also the amount of retained deuterium is higher in the tiles located in the upper and lower regions of the plasma chamber.
Original languageEnglish
Pages (from-to)2557-2560
Number of pages4
JournalFusion Engineering and Design
Volume86
Issue number9-11
DOIs
Publication statusPublished - 2011
MoE publication typeA1 Journal article-refereed
Event26th Symposium of Fusion Technology, SOFT-26 - Porto, Portugal
Duration: 27 Sep 20101 Oct 2010
Conference number: 26

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Plasma interactions
Tile
Surface structure
Surface morphology
Erosion
Limiters
Plasmas
Chlorofluorocarbons
Deuterium
Ion beams
Electron microscopy
Tungsten
Fusion reactions
Irradiation
Carbon

Keywords

  • Ion beam analysis
  • Carbon fibre composites tiles
  • Fusion reactor materials

Cite this

JET-EFDA collaborators. / Surface composition and morphology changes of JET tiles under plasma interactions. In: Fusion Engineering and Design. 2011 ; Vol. 86, No. 9-11. pp. 2557-2560.
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abstract = "Plasma interactions with the main chamber of magnetic fusion devices result in net erosion from some areas and net deposition at other locations. However, high energy particle irradiation means that there are continuous erosion and re-deposition processes involved, creating new surface structures. Although the net deposition can be readily assessed, net erosion and material mixing is difficult to determine. In 2005 marker tiles were mounted in the JET vessel which have a thin tungsten (W) layer deposited on the CFC substrate with a ∼10 μm carbon layer on top. This layered structure was designed to determine the areas where some erosion had occurred during JET plasma operations, when the tiles were removed for analysis in 2007.This paper describes the results from a set of tiles mounted in a poloidal limiter (in Octant 8) at the outer wall of the main chamber; a comparison is made between the data from tiles near the top, middle and bottom of the limiter. A set of ion beam techniques together with electron microscopy were used to provide a detailed analysis of the tiles. In general, since plasma interaction is strongest near the centre of the limiter where the tile is closest to the boundary of the confined plasma, erosion dominated on the central tiles, with deposition further from the plasma boundary. Also the amount of retained deuterium is higher in the tiles located in the upper and lower regions of the plasma chamber.",
keywords = "Ion beam analysis, Carbon fibre composites tiles, Fusion reactor materials",
author = "Alves, {L. C.} and E. Alves and Barradas, {N. P.} and M. Dias and R. Mateus and P. Carvalho and Coad, {J. P.} and Widdowson, {A. M.} and Jari Likonen and Seppo Koivuranta and {JET-EFDA collaborators}",
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Surface composition and morphology changes of JET tiles under plasma interactions. / JET-EFDA collaborators.

In: Fusion Engineering and Design, Vol. 86, No. 9-11, 2011, p. 2557-2560.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Surface composition and morphology changes of JET tiles under plasma interactions

AU - Alves, L. C.

AU - Alves, E.

AU - Barradas, N. P.

AU - Dias, M.

AU - Mateus, R.

AU - Carvalho, P.

AU - Coad, J. P.

AU - Widdowson, A. M.

AU - Likonen, Jari

AU - Koivuranta, Seppo

AU - JET-EFDA collaborators

PY - 2011

Y1 - 2011

N2 - Plasma interactions with the main chamber of magnetic fusion devices result in net erosion from some areas and net deposition at other locations. However, high energy particle irradiation means that there are continuous erosion and re-deposition processes involved, creating new surface structures. Although the net deposition can be readily assessed, net erosion and material mixing is difficult to determine. In 2005 marker tiles were mounted in the JET vessel which have a thin tungsten (W) layer deposited on the CFC substrate with a ∼10 μm carbon layer on top. This layered structure was designed to determine the areas where some erosion had occurred during JET plasma operations, when the tiles were removed for analysis in 2007.This paper describes the results from a set of tiles mounted in a poloidal limiter (in Octant 8) at the outer wall of the main chamber; a comparison is made between the data from tiles near the top, middle and bottom of the limiter. A set of ion beam techniques together with electron microscopy were used to provide a detailed analysis of the tiles. In general, since plasma interaction is strongest near the centre of the limiter where the tile is closest to the boundary of the confined plasma, erosion dominated on the central tiles, with deposition further from the plasma boundary. Also the amount of retained deuterium is higher in the tiles located in the upper and lower regions of the plasma chamber.

AB - Plasma interactions with the main chamber of magnetic fusion devices result in net erosion from some areas and net deposition at other locations. However, high energy particle irradiation means that there are continuous erosion and re-deposition processes involved, creating new surface structures. Although the net deposition can be readily assessed, net erosion and material mixing is difficult to determine. In 2005 marker tiles were mounted in the JET vessel which have a thin tungsten (W) layer deposited on the CFC substrate with a ∼10 μm carbon layer on top. This layered structure was designed to determine the areas where some erosion had occurred during JET plasma operations, when the tiles were removed for analysis in 2007.This paper describes the results from a set of tiles mounted in a poloidal limiter (in Octant 8) at the outer wall of the main chamber; a comparison is made between the data from tiles near the top, middle and bottom of the limiter. A set of ion beam techniques together with electron microscopy were used to provide a detailed analysis of the tiles. In general, since plasma interaction is strongest near the centre of the limiter where the tile is closest to the boundary of the confined plasma, erosion dominated on the central tiles, with deposition further from the plasma boundary. Also the amount of retained deuterium is higher in the tiles located in the upper and lower regions of the plasma chamber.

KW - Ion beam analysis

KW - Carbon fibre composites tiles

KW - Fusion reactor materials

U2 - 10.1016/j.fusengdes.2011.03.093

DO - 10.1016/j.fusengdes.2011.03.093

M3 - Article

VL - 86

SP - 2557

EP - 2560

JO - Fusion Engineering and Design

JF - Fusion Engineering and Design

SN - 0920-3796

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