Experimental estimation of tungsten impurity sputtering due to Type I ELMs in JET-ITER-like wall using pedestal electron cyclotron emission and target Langmuir probe measurements

C Guillemaut, A Jardin, J Horacek, I Borodkina, A Autricque, G Arnoux, J Boom, S Brezinsek, J W Coenen, E De La Luna, S Devaux, T Eich, D Harting, A Kirschner, B Lipschultz, G F Matthews, A Meigs, D Moulton, M O'Mullane, M Stamp

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The ITER baseline scenario, with 500 MW of DT fusion power and Q = 10, will rely on a Type I ELMy H-mode and will be achieved with a tungsten (W) divertor. W atoms sputtered from divertor targets during mitigated ELMs are expected to be the dominant source in ITER. W impurity concentration in the plasma core can dramatically degrade its performance and lead to potentially damaging disruptions. Understanding the physics of the target W source due to sputtering during ELMs and inter-ELMs is important and can be helped by experimental measurements with improved precision. It has been established that the ELMy target ion impact energy has a simple linear dependence with the pedestal electron temperature measured by Electron Cyclotron Emission (ECE). It has also been shown that Langmuir Probes (LP) ion flux measurements are reliable during ELMs due to the surprisingly low electron temperature. Therefore, in this paper, LP and ECE measurements in JET-ITER-Like-Wall (ILW) unseeded Type I ELMy H-mode experiments have been used to estimate the W sputtering flux from divertor targets in ELM and inter-ELM conditions. Comparison with similar estimates using W I spectroscopy measurements shows a reasonable agreement for the ELM and inter-ELM W source. The main advantage of the method involving LP measurements is the very high time resolution of the diagnostic (∼10 μs) allowing very precise description of the W sputtering source during ELMs.

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Sputtering
electrostatic probes
Impurities
cyclotrons
tungsten
Probe
sputtering
Electron
impurities
Target
electrons
electron energy
Linear dependence
ion impact
estimates
Estimate
Spectroscopy
Baseline
Diagnostics
Fusion

Keywords

  • edge localized mode
  • magnetic confinement fusion
  • tungsten sputtering

Cite this

Guillemaut, C ; Jardin, A ; Horacek, J ; Borodkina, I ; Autricque, A ; Arnoux, G ; Boom, J ; Brezinsek, S ; Coenen, J W ; De La Luna, E ; Devaux, S ; Eich, T ; Harting, D ; Kirschner, A ; Lipschultz, B ; Matthews, G F ; Meigs, A ; Moulton, D ; O'Mullane, M ; Stamp, M. / Experimental estimation of tungsten impurity sputtering due to Type I ELMs in JET-ITER-like wall using pedestal electron cyclotron emission and target Langmuir probe measurements. In: Physica Scripta. 2016 ; Vol. 2016, No. T167.
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title = "Experimental estimation of tungsten impurity sputtering due to Type I ELMs in JET-ITER-like wall using pedestal electron cyclotron emission and target Langmuir probe measurements",
abstract = "The ITER baseline scenario, with 500 MW of DT fusion power and Q = 10, will rely on a Type I ELMy H-mode and will be achieved with a tungsten (W) divertor. W atoms sputtered from divertor targets during mitigated ELMs are expected to be the dominant source in ITER. W impurity concentration in the plasma core can dramatically degrade its performance and lead to potentially damaging disruptions. Understanding the physics of the target W source due to sputtering during ELMs and inter-ELMs is important and can be helped by experimental measurements with improved precision. It has been established that the ELMy target ion impact energy has a simple linear dependence with the pedestal electron temperature measured by Electron Cyclotron Emission (ECE). It has also been shown that Langmuir Probes (LP) ion flux measurements are reliable during ELMs due to the surprisingly low electron temperature. Therefore, in this paper, LP and ECE measurements in JET-ITER-Like-Wall (ILW) unseeded Type I ELMy H-mode experiments have been used to estimate the W sputtering flux from divertor targets in ELM and inter-ELM conditions. Comparison with similar estimates using W I spectroscopy measurements shows a reasonable agreement for the ELM and inter-ELM W source. The main advantage of the method involving LP measurements is the very high time resolution of the diagnostic (∼10 μs) allowing very precise description of the W sputtering source during ELMs.",
keywords = "edge localized mode, magnetic confinement fusion, tungsten sputtering",
author = "C Guillemaut and A Jardin and J Horacek and I Borodkina and A Autricque and G Arnoux and J Boom and S Brezinsek and Coenen, {J W} and {De La Luna}, E and S Devaux and T Eich and D Harting and A Kirschner and B Lipschultz and Matthews, {G F} and A Meigs and D Moulton and M O'Mullane and M Stamp",
note = "This is an author-created, un-copyedited version of an article published in Physica Scripta. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0031-8949/2015/T167/014005",
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Guillemaut, C, Jardin, A, Horacek, J, Borodkina, I, Autricque, A, Arnoux, G, Boom, J, Brezinsek, S, Coenen, JW, De La Luna, E, Devaux, S, Eich, T, Harting, D, Kirschner, A, Lipschultz, B, Matthews, GF, Meigs, A, Moulton, D, O'Mullane, M & Stamp, M 2016, 'Experimental estimation of tungsten impurity sputtering due to Type I ELMs in JET-ITER-like wall using pedestal electron cyclotron emission and target Langmuir probe measurements' Physica Scripta, vol. 2016, no. T167. https://doi.org/10.1088/0031-8949/2015/T167/014005

Experimental estimation of tungsten impurity sputtering due to Type I ELMs in JET-ITER-like wall using pedestal electron cyclotron emission and target Langmuir probe measurements. / Guillemaut, C; Jardin, A; Horacek, J; Borodkina, I; Autricque, A; Arnoux, G; Boom, J; Brezinsek, S; Coenen, J W; De La Luna, E; Devaux, S; Eich, T; Harting, D; Kirschner, A; Lipschultz, B; Matthews, G F; Meigs, A; Moulton, D; O'Mullane, M; Stamp, M.

In: Physica Scripta, Vol. 2016, No. T167, 08.01.2016.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Experimental estimation of tungsten impurity sputtering due to Type I ELMs in JET-ITER-like wall using pedestal electron cyclotron emission and target Langmuir probe measurements

AU - Guillemaut, C

AU - Jardin, A

AU - Horacek, J

AU - Borodkina, I

AU - Autricque, A

AU - Arnoux, G

AU - Boom, J

AU - Brezinsek, S

AU - Coenen, J W

AU - De La Luna, E

AU - Devaux, S

AU - Eich, T

AU - Harting, D

AU - Kirschner, A

AU - Lipschultz, B

AU - Matthews, G F

AU - Meigs, A

AU - Moulton, D

AU - O'Mullane, M

AU - Stamp, M

N1 - This is an author-created, un-copyedited version of an article published in Physica Scripta. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0031-8949/2015/T167/014005

PY - 2016/1/8

Y1 - 2016/1/8

N2 - The ITER baseline scenario, with 500 MW of DT fusion power and Q = 10, will rely on a Type I ELMy H-mode and will be achieved with a tungsten (W) divertor. W atoms sputtered from divertor targets during mitigated ELMs are expected to be the dominant source in ITER. W impurity concentration in the plasma core can dramatically degrade its performance and lead to potentially damaging disruptions. Understanding the physics of the target W source due to sputtering during ELMs and inter-ELMs is important and can be helped by experimental measurements with improved precision. It has been established that the ELMy target ion impact energy has a simple linear dependence with the pedestal electron temperature measured by Electron Cyclotron Emission (ECE). It has also been shown that Langmuir Probes (LP) ion flux measurements are reliable during ELMs due to the surprisingly low electron temperature. Therefore, in this paper, LP and ECE measurements in JET-ITER-Like-Wall (ILW) unseeded Type I ELMy H-mode experiments have been used to estimate the W sputtering flux from divertor targets in ELM and inter-ELM conditions. Comparison with similar estimates using W I spectroscopy measurements shows a reasonable agreement for the ELM and inter-ELM W source. The main advantage of the method involving LP measurements is the very high time resolution of the diagnostic (∼10 μs) allowing very precise description of the W sputtering source during ELMs.

AB - The ITER baseline scenario, with 500 MW of DT fusion power and Q = 10, will rely on a Type I ELMy H-mode and will be achieved with a tungsten (W) divertor. W atoms sputtered from divertor targets during mitigated ELMs are expected to be the dominant source in ITER. W impurity concentration in the plasma core can dramatically degrade its performance and lead to potentially damaging disruptions. Understanding the physics of the target W source due to sputtering during ELMs and inter-ELMs is important and can be helped by experimental measurements with improved precision. It has been established that the ELMy target ion impact energy has a simple linear dependence with the pedestal electron temperature measured by Electron Cyclotron Emission (ECE). It has also been shown that Langmuir Probes (LP) ion flux measurements are reliable during ELMs due to the surprisingly low electron temperature. Therefore, in this paper, LP and ECE measurements in JET-ITER-Like-Wall (ILW) unseeded Type I ELMy H-mode experiments have been used to estimate the W sputtering flux from divertor targets in ELM and inter-ELM conditions. Comparison with similar estimates using W I spectroscopy measurements shows a reasonable agreement for the ELM and inter-ELM W source. The main advantage of the method involving LP measurements is the very high time resolution of the diagnostic (∼10 μs) allowing very precise description of the W sputtering source during ELMs.

KW - edge localized mode

KW - magnetic confinement fusion

KW - tungsten sputtering

UR - http://www.scopus.com/inward/record.url?scp=84959888195&partnerID=8YFLogxK

UR - http://iopscience.iop.org/journal/1402-4896

UR - http://irfm.cea.fr/pfmc15/

U2 - 10.1088/0031-8949/2015/T167/014005

DO - 10.1088/0031-8949/2015/T167/014005

M3 - Article

VL - 2016

JO - Physica Scripta

T2 - Physica Scripta

JF - Physica Scripta

SN - 0031-8949

IS - T167

ER -