Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST

S. K. Sharma, H. Zushi, N. Yoshida, Hideo Watanabe, M. Osakabe, Y. Takeri, Makoto Hasegawa, T. Tanabe, Kazutoshi Tokunaga, Kazuaki Hanada, Hiroshi Idei, M. Sakamoto, Kazuo Nakamura, akihide fujisawa, M. Ishiguro, S. Tashima

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

After several non-inductive current startup experimental campaigns in the spherical tokamak QUEST, its metallic first walls have revealed various kinds of damages as a signature of strong plasma wall interaction (PWI). Several types of footprint traces, namely colored regions formed due to material erosion/redeposition, melting of plasma facing components (PFCs) and numerous arc tracks on the chamber walls are recognized. Analysis of the re-deposited materials on collector probes is carried out using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Redeposition of several impurity materials such as carbon, oxygen and tungsten is identified. The footprint traces are majorly formed on the lower side PFCs, showing a large up/down asymmetry. Both toroidally symmetric and asymmetric footprint traces are formed on the bottoms side divertor plate and the lower part of the outboard side walls, respectively. Localized melting occurred on the outboard side limiters is attributed to the loss of energetic electrons produced via electron cyclotron resonance (ECR) heating. The observed damages are discussed in view of localized PWI, loss of energetic electrons, particle drifts, sputtering, arcing and redeposition of eroded materials. Material analysis and numerically calculated guiding center orbits of the charge particles are used to discuss these damages.

Original languageEnglish
Pages (from-to)77-86
Number of pages10
JournalFusion Engineering and Design
Volume87
Issue number1
DOIs
Publication statusPublished - Jan 1 2012

Fingerprint

Beam plasma interactions
Plasmas
Melting
Tungsten
Electron cyclotron resonance
Electrons
Limiters
Sputtering
Energy dispersive spectroscopy
Erosion
Orbits
Carbon
X ray photoelectron spectroscopy
Impurities
Oxygen
Heating
Scanning electron microscopy

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST. / Sharma, S. K.; Zushi, H.; Yoshida, N.; Watanabe, Hideo; Osakabe, M.; Takeri, Y.; Hasegawa, Makoto; Tanabe, T.; Tokunaga, Kazutoshi; Hanada, Kazuaki; Idei, Hiroshi; Sakamoto, M.; Nakamura, Kazuo; fujisawa, akihide; Ishiguro, M.; Tashima, S.

In: Fusion Engineering and Design, Vol. 87, No. 1, 01.01.2012, p. 77-86.

Research output: Contribution to journalArticle

Sharma, S. K. ; Zushi, H. ; Yoshida, N. ; Watanabe, Hideo ; Osakabe, M. ; Takeri, Y. ; Hasegawa, Makoto ; Tanabe, T. ; Tokunaga, Kazutoshi ; Hanada, Kazuaki ; Idei, Hiroshi ; Sakamoto, M. ; Nakamura, Kazuo ; fujisawa, akihide ; Ishiguro, M. ; Tashima, S. / Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST. In: Fusion Engineering and Design. 2012 ; Vol. 87, No. 1. pp. 77-86.
@article{2e75bd5a1d6d4d7fbc63f8f6ac1fbd8c,
title = "Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST",
abstract = "After several non-inductive current startup experimental campaigns in the spherical tokamak QUEST, its metallic first walls have revealed various kinds of damages as a signature of strong plasma wall interaction (PWI). Several types of footprint traces, namely colored regions formed due to material erosion/redeposition, melting of plasma facing components (PFCs) and numerous arc tracks on the chamber walls are recognized. Analysis of the re-deposited materials on collector probes is carried out using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Redeposition of several impurity materials such as carbon, oxygen and tungsten is identified. The footprint traces are majorly formed on the lower side PFCs, showing a large up/down asymmetry. Both toroidally symmetric and asymmetric footprint traces are formed on the bottoms side divertor plate and the lower part of the outboard side walls, respectively. Localized melting occurred on the outboard side limiters is attributed to the loss of energetic electrons produced via electron cyclotron resonance (ECR) heating. The observed damages are discussed in view of localized PWI, loss of energetic electrons, particle drifts, sputtering, arcing and redeposition of eroded materials. Material analysis and numerically calculated guiding center orbits of the charge particles are used to discuss these damages.",
author = "Sharma, {S. K.} and H. Zushi and N. Yoshida and Hideo Watanabe and M. Osakabe and Y. Takeri and Makoto Hasegawa and T. Tanabe and Kazutoshi Tokunaga and Kazuaki Hanada and Hiroshi Idei and M. Sakamoto and Kazuo Nakamura and akihide fujisawa and M. Ishiguro and S. Tashima",
year = "2012",
month = "1",
day = "1",
doi = "10.1016/j.fusengdes.2011.10.001",
language = "English",
volume = "87",
pages = "77--86",
journal = "Fusion Engineering and Design",
issn = "0920-3796",
publisher = "Elsevier BV",
number = "1",

}

TY - JOUR

T1 - Analysis of PWI footprint traces and material damage on the first walls of the spherical tokamak QUEST

AU - Sharma, S. K.

AU - Zushi, H.

AU - Yoshida, N.

AU - Watanabe, Hideo

AU - Osakabe, M.

AU - Takeri, Y.

AU - Hasegawa, Makoto

AU - Tanabe, T.

AU - Tokunaga, Kazutoshi

AU - Hanada, Kazuaki

AU - Idei, Hiroshi

AU - Sakamoto, M.

AU - Nakamura, Kazuo

AU - fujisawa, akihide

AU - Ishiguro, M.

AU - Tashima, S.

PY - 2012/1/1

Y1 - 2012/1/1

N2 - After several non-inductive current startup experimental campaigns in the spherical tokamak QUEST, its metallic first walls have revealed various kinds of damages as a signature of strong plasma wall interaction (PWI). Several types of footprint traces, namely colored regions formed due to material erosion/redeposition, melting of plasma facing components (PFCs) and numerous arc tracks on the chamber walls are recognized. Analysis of the re-deposited materials on collector probes is carried out using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Redeposition of several impurity materials such as carbon, oxygen and tungsten is identified. The footprint traces are majorly formed on the lower side PFCs, showing a large up/down asymmetry. Both toroidally symmetric and asymmetric footprint traces are formed on the bottoms side divertor plate and the lower part of the outboard side walls, respectively. Localized melting occurred on the outboard side limiters is attributed to the loss of energetic electrons produced via electron cyclotron resonance (ECR) heating. The observed damages are discussed in view of localized PWI, loss of energetic electrons, particle drifts, sputtering, arcing and redeposition of eroded materials. Material analysis and numerically calculated guiding center orbits of the charge particles are used to discuss these damages.

AB - After several non-inductive current startup experimental campaigns in the spherical tokamak QUEST, its metallic first walls have revealed various kinds of damages as a signature of strong plasma wall interaction (PWI). Several types of footprint traces, namely colored regions formed due to material erosion/redeposition, melting of plasma facing components (PFCs) and numerous arc tracks on the chamber walls are recognized. Analysis of the re-deposited materials on collector probes is carried out using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Redeposition of several impurity materials such as carbon, oxygen and tungsten is identified. The footprint traces are majorly formed on the lower side PFCs, showing a large up/down asymmetry. Both toroidally symmetric and asymmetric footprint traces are formed on the bottoms side divertor plate and the lower part of the outboard side walls, respectively. Localized melting occurred on the outboard side limiters is attributed to the loss of energetic electrons produced via electron cyclotron resonance (ECR) heating. The observed damages are discussed in view of localized PWI, loss of energetic electrons, particle drifts, sputtering, arcing and redeposition of eroded materials. Material analysis and numerically calculated guiding center orbits of the charge particles are used to discuss these damages.

UR - http://www.scopus.com/inward/record.url?scp=83555174792&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=83555174792&partnerID=8YFLogxK

U2 - 10.1016/j.fusengdes.2011.10.001

DO - 10.1016/j.fusengdes.2011.10.001

M3 - Article

AN - SCOPUS:83555174792

VL - 87

SP - 77

EP - 86

JO - Fusion Engineering and Design

JF - Fusion Engineering and Design

SN - 0920-3796

IS - 1

ER -