Method for experimental determination of Z dependence of impurity transport on JET

C. Giroud, R. Barnsley, P. Buratti, I.H. Coffey, M. von Hellermann, C. Jupen, K.D. Lawson, A. Meigs, M. O'Mullane, A.D. Whiteford, K.-D. Zastrow, JET EFDA Contributors

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The prediction of impurity peaking in future fusion devices such as ITER necessitates the study of the dependence on Z of the impurity transport in present devices. In this paper we describe a novel technique to determine the transport of impurities with different atomic numbers independently. A technique has been developed that allows simultaneously the measurement of the transport of Ne and Ar in the same discharge while minimizing the systematic errors in the spectroscopic measurements. The reproduction of the charge-exchange measured densities, absolute vaccum ultra-violet line intensities and absolute soft x-ray intensity is achieved in an impurity transport simulation. The method used to estimate the errors on the transport coefficients of neon (Ne) and argon (Ar) is presented. In the plasma region where the diffusion and convection coefficients are determined for hybrid discharges, the transport of Ne and Ar is observed to exceed neoclassical predictions. In the same regions, the diffusion coefficients of both impurities are similar. The convection coefficients are also comparable for Ne and Ar. The peaking of Ne and Ar density profiles are comparable during the period where the intermittent slow reconnecting n = 1 mode is stable in these hybrid discharges.
LanguageEnglish
Pages313-330
Number of pages18
JournalNuclear Fusion
Volume47
Issue number4
DOIs
Publication statusPublished - 1 Apr 2007

Fingerprint

neon
argon
impurities
convection
diffusion coefficient
coefficients
predictions
charge exchange
systematic errors
fusion
transport properties
estimates
profiles
x rays
simulation

Keywords

  • spherical tokamaks
  • impurities in plasmas
  • plasma diagnostic techniques
  • plasma diagnostic instrumentation

Cite this

Giroud, C., Barnsley, R., Buratti, P., Coffey, I. H., von Hellermann, M., Jupen, C., ... Contributors, JET. EFDA. (2007). Method for experimental determination of Z dependence of impurity transport on JET. Nuclear Fusion, 47(4), 313-330. https://doi.org/10.1088/0029-5515/47/4/010
Giroud, C. ; Barnsley, R. ; Buratti, P. ; Coffey, I.H. ; von Hellermann, M. ; Jupen, C. ; Lawson, K.D. ; Meigs, A. ; O'Mullane, M. ; Whiteford, A.D. ; Zastrow, K.-D. ; Contributors, JET EFDA. / Method for experimental determination of Z dependence of impurity transport on JET. In: Nuclear Fusion. 2007 ; Vol. 47, No. 4. pp. 313-330.
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Giroud, C, Barnsley, R, Buratti, P, Coffey, IH, von Hellermann, M, Jupen, C, Lawson, KD, Meigs, A, O'Mullane, M, Whiteford, AD, Zastrow, K-D & Contributors, JETEFDA 2007, 'Method for experimental determination of Z dependence of impurity transport on JET' Nuclear Fusion, vol. 47, no. 4, pp. 313-330. https://doi.org/10.1088/0029-5515/47/4/010

Method for experimental determination of Z dependence of impurity transport on JET. / Giroud, C.; Barnsley, R.; Buratti, P.; Coffey, I.H.; von Hellermann, M.; Jupen, C.; Lawson, K.D.; Meigs, A.; O'Mullane, M.; Whiteford, A.D.; Zastrow, K.-D.; Contributors, JET EFDA.

In: Nuclear Fusion, Vol. 47, No. 4, 01.04.2007, p. 313-330.

Research output: Contribution to journalArticle

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T1 - Method for experimental determination of Z dependence of impurity transport on JET

AU - Giroud, C.

AU - Barnsley, R.

AU - Buratti, P.

AU - Coffey, I.H.

AU - von Hellermann, M.

AU - Jupen, C.

AU - Lawson, K.D.

AU - Meigs, A.

AU - O'Mullane, M.

AU - Whiteford, A.D.

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N2 - The prediction of impurity peaking in future fusion devices such as ITER necessitates the study of the dependence on Z of the impurity transport in present devices. In this paper we describe a novel technique to determine the transport of impurities with different atomic numbers independently. A technique has been developed that allows simultaneously the measurement of the transport of Ne and Ar in the same discharge while minimizing the systematic errors in the spectroscopic measurements. The reproduction of the charge-exchange measured densities, absolute vaccum ultra-violet line intensities and absolute soft x-ray intensity is achieved in an impurity transport simulation. The method used to estimate the errors on the transport coefficients of neon (Ne) and argon (Ar) is presented. In the plasma region where the diffusion and convection coefficients are determined for hybrid discharges, the transport of Ne and Ar is observed to exceed neoclassical predictions. In the same regions, the diffusion coefficients of both impurities are similar. The convection coefficients are also comparable for Ne and Ar. The peaking of Ne and Ar density profiles are comparable during the period where the intermittent slow reconnecting n = 1 mode is stable in these hybrid discharges.

AB - The prediction of impurity peaking in future fusion devices such as ITER necessitates the study of the dependence on Z of the impurity transport in present devices. In this paper we describe a novel technique to determine the transport of impurities with different atomic numbers independently. A technique has been developed that allows simultaneously the measurement of the transport of Ne and Ar in the same discharge while minimizing the systematic errors in the spectroscopic measurements. The reproduction of the charge-exchange measured densities, absolute vaccum ultra-violet line intensities and absolute soft x-ray intensity is achieved in an impurity transport simulation. The method used to estimate the errors on the transport coefficients of neon (Ne) and argon (Ar) is presented. In the plasma region where the diffusion and convection coefficients are determined for hybrid discharges, the transport of Ne and Ar is observed to exceed neoclassical predictions. In the same regions, the diffusion coefficients of both impurities are similar. The convection coefficients are also comparable for Ne and Ar. The peaking of Ne and Ar density profiles are comparable during the period where the intermittent slow reconnecting n = 1 mode is stable in these hybrid discharges.

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KW - plasma diagnostic instrumentation

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T2 - Nuclear Fusion

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Giroud C, Barnsley R, Buratti P, Coffey IH, von Hellermann M, Jupen C et al. Method for experimental determination of Z dependence of impurity transport on JET. Nuclear Fusion. 2007 Apr 1;47(4):313-330. https://doi.org/10.1088/0029-5515/47/4/010