Overview and interpretation of L-H threshold experiments on JET with the ITER-like Wall

E. Delabie, C. Maggi, H. Meyer, T.M. Biewer, C. Bourdelle, M. Brix, I.S. Carvalho, M. Cleber, P. Drewelow, N. Hawkes, J. Hillesheim, A. Meigs, L. Meneses, F. Rimini, Paula Siren, E. Solano, M. Stamp

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

    Abstract

    The expected threshold power (PL􀀀H) required to access H-mode operation on ITER is extrapolated from a multi-machine scaling that is strongly weighted to a dataset of JET carbon wall discharges [1]. Experiments on JET with the Be/W wall show a minimum in PL􀀀H as function of density and a favorable reduction in the threshold power of 30% at medium to high densities [2]. The carbon wall threshold can be recovered with nitrogen injection. An increase in the threshold power by up to a factor 2 and a reduction of the density at which the minimum occurs was found when the outer strike point position was moved from the horizontal to the vertical target. The existence of a critical min(Er;dia) is consistent with the threshold data from each of the divertor congurations but does not explain the dierences between them. The observation of a strong asymmetry between the inner and outer divertor that develops during a power ramp is correlated with the L-H threshold in the high density branch and indicates a direct eect of the scrape o layer or divertor conditions on the threshold. This mechanism also provides a qualitative explanation for dithering L-H transitions.
    Original languageEnglish
    Title of host publication25th IAEA Fusion Energy Conference
    Subtitle of host publicationProgramme, Abstracts, and Contributions
    PublisherInternational Atomic Energy Agency IAEA
    PagesEX/P5-24
    Number of pages8
    Publication statusPublished - 2014
    MoE publication typeB3 Non-refereed article in conference proceedings
    Event25th Fusion Energy Conference, IAEA FEC 2014 - St.Petersburg, Russian Federation
    Duration: 13 Oct 201418 Oct 2014
    http://www-naweb.iaea.org/napc/physics/FEC/FEC2014/fec_sourcebook_online.pdf (Full proceedings)

    Conference

    Conference25th Fusion Energy Conference, IAEA FEC 2014
    Abbreviated titleIAEA FEC 2014
    CountryRussian Federation
    CitySt.Petersburg
    Period13/10/1418/10/14
    Internet address

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    thresholds
    carbon
    ramps
    asymmetry
    injection
    scaling
    nitrogen

    Cite this

    Delabie, E., Maggi, C., Meyer, H., Biewer, T. M., Bourdelle, C., Brix, M., ... Stamp, M. (2014). Overview and interpretation of L-H threshold experiments on JET with the ITER-like Wall. In 25th IAEA Fusion Energy Conference: Programme, Abstracts, and Contributions (pp. EX/P5-24). International Atomic Energy Agency IAEA.
    Delabie, E. ; Maggi, C. ; Meyer, H. ; Biewer, T.M. ; Bourdelle, C. ; Brix, M. ; Carvalho, I.S. ; Cleber, M. ; Drewelow, P. ; Hawkes, N. ; Hillesheim, J. ; Meigs, A. ; Meneses, L. ; Rimini, F. ; Siren, Paula ; Solano, E. ; Stamp, M. / Overview and interpretation of L-H threshold experiments on JET with the ITER-like Wall. 25th IAEA Fusion Energy Conference: Programme, Abstracts, and Contributions. International Atomic Energy Agency IAEA, 2014. pp. EX/P5-24
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    abstract = "The expected threshold power (PL􀀀H) required to access H-mode operation on ITER is extrapolated from a multi-machine scaling that is strongly weighted to a dataset of JET carbon wall discharges [1]. Experiments on JET with the Be/W wall show a minimum in PL􀀀H as function of density and a favorable reduction in the threshold power of 30{\%} at medium to high densities [2]. The carbon wall threshold can be recovered with nitrogen injection. An increase in the threshold power by up to a factor 2 and a reduction of the density at which the minimum occurs was found when the outer strike point position was moved from the horizontal to the vertical target. The existence of a critical min(Er;dia) is consistent with the threshold data from each of the divertor congurations but does not explain the dierences between them. The observation of a strong asymmetry between the inner and outer divertor that develops during a power ramp is correlated with the L-H threshold in the high density branch and indicates a direct eect of the scrape o layer or divertor conditions on the threshold. This mechanism also provides a qualitative explanation for dithering L-H transitions.",
    author = "E. Delabie and C. Maggi and H. Meyer and T.M. Biewer and C. Bourdelle and M. Brix and I.S. Carvalho and M. Cleber and P. Drewelow and N. Hawkes and J. Hillesheim and A. Meigs and L. Meneses and F. Rimini and Paula Siren and E. Solano and M. Stamp",
    note = "HUO: Poster presentation CO:U FOM Institute DIFFER, Association EURATOM-FOM, Nieuwegein, The Netherlands CO:Max-Planck-Institut f{\"u}r Plasmaphysik, Germany CO:Culham Science Centre, United Kingdom CO:Oak Ridge National Laboratory, TN, USA CO:U CEA-IRFM, Saint Paul lez Durance, France CO:Culham Science Centre, United Kingdom CO:U Institute of Plasmas and Nuclear Fusion, Association EURATOM/IST, Lisbon, Portugal CO:Forschungszentrum J{\"u}lich GmbH, Germany CO:Max-Planck-Institut f{\"u}r Plasmaphysik, Germany CO:U The National Fusion Laboratory, CIEMAT, Madrid, Spain CA2: BA2121",
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    Delabie, E, Maggi, C, Meyer, H, Biewer, TM, Bourdelle, C, Brix, M, Carvalho, IS, Cleber, M, Drewelow, P, Hawkes, N, Hillesheim, J, Meigs, A, Meneses, L, Rimini, F, Siren, P, Solano, E & Stamp, M 2014, Overview and interpretation of L-H threshold experiments on JET with the ITER-like Wall. in 25th IAEA Fusion Energy Conference: Programme, Abstracts, and Contributions. International Atomic Energy Agency IAEA, pp. EX/P5-24, 25th Fusion Energy Conference, IAEA FEC 2014, St.Petersburg, Russian Federation, 13/10/14.

    Overview and interpretation of L-H threshold experiments on JET with the ITER-like Wall. / Delabie, E.; Maggi, C.; Meyer, H.; Biewer, T.M.; Bourdelle, C.; Brix, M.; Carvalho, I.S.; Cleber, M.; Drewelow, P.; Hawkes, N.; Hillesheim, J.; Meigs, A.; Meneses, L.; Rimini, F.; Siren, Paula; Solano, E.; Stamp, M.

    25th IAEA Fusion Energy Conference: Programme, Abstracts, and Contributions. International Atomic Energy Agency IAEA, 2014. p. EX/P5-24.

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

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    AU - Maggi, C.

    AU - Meyer, H.

    AU - Biewer, T.M.

    AU - Bourdelle, C.

    AU - Brix, M.

    AU - Carvalho, I.S.

    AU - Cleber, M.

    AU - Drewelow, P.

    AU - Hawkes, N.

    AU - Hillesheim, J.

    AU - Meigs, A.

    AU - Meneses, L.

    AU - Rimini, F.

    AU - Siren, Paula

    AU - Solano, E.

    AU - Stamp, M.

    N1 - HUO: Poster presentation CO:U FOM Institute DIFFER, Association EURATOM-FOM, Nieuwegein, The Netherlands CO:Max-Planck-Institut für Plasmaphysik, Germany CO:Culham Science Centre, United Kingdom CO:Oak Ridge National Laboratory, TN, USA CO:U CEA-IRFM, Saint Paul lez Durance, France CO:Culham Science Centre, United Kingdom CO:U Institute of Plasmas and Nuclear Fusion, Association EURATOM/IST, Lisbon, Portugal CO:Forschungszentrum Jülich GmbH, Germany CO:Max-Planck-Institut für Plasmaphysik, Germany CO:U The National Fusion Laboratory, CIEMAT, Madrid, Spain CA2: BA2121

    PY - 2014

    Y1 - 2014

    N2 - The expected threshold power (PL􀀀H) required to access H-mode operation on ITER is extrapolated from a multi-machine scaling that is strongly weighted to a dataset of JET carbon wall discharges [1]. Experiments on JET with the Be/W wall show a minimum in PL􀀀H as function of density and a favorable reduction in the threshold power of 30% at medium to high densities [2]. The carbon wall threshold can be recovered with nitrogen injection. An increase in the threshold power by up to a factor 2 and a reduction of the density at which the minimum occurs was found when the outer strike point position was moved from the horizontal to the vertical target. The existence of a critical min(Er;dia) is consistent with the threshold data from each of the divertor congurations but does not explain the dierences between them. The observation of a strong asymmetry between the inner and outer divertor that develops during a power ramp is correlated with the L-H threshold in the high density branch and indicates a direct eect of the scrape o layer or divertor conditions on the threshold. This mechanism also provides a qualitative explanation for dithering L-H transitions.

    AB - The expected threshold power (PL􀀀H) required to access H-mode operation on ITER is extrapolated from a multi-machine scaling that is strongly weighted to a dataset of JET carbon wall discharges [1]. Experiments on JET with the Be/W wall show a minimum in PL􀀀H as function of density and a favorable reduction in the threshold power of 30% at medium to high densities [2]. The carbon wall threshold can be recovered with nitrogen injection. An increase in the threshold power by up to a factor 2 and a reduction of the density at which the minimum occurs was found when the outer strike point position was moved from the horizontal to the vertical target. The existence of a critical min(Er;dia) is consistent with the threshold data from each of the divertor congurations but does not explain the dierences between them. The observation of a strong asymmetry between the inner and outer divertor that develops during a power ramp is correlated with the L-H threshold in the high density branch and indicates a direct eect of the scrape o layer or divertor conditions on the threshold. This mechanism also provides a qualitative explanation for dithering L-H transitions.

    M3 - Conference article in proceedings

    SP - EX/P5-24

    BT - 25th IAEA Fusion Energy Conference

    PB - International Atomic Energy Agency IAEA

    ER -

    Delabie E, Maggi C, Meyer H, Biewer TM, Bourdelle C, Brix M et al. Overview and interpretation of L-H threshold experiments on JET with the ITER-like Wall. In 25th IAEA Fusion Energy Conference: Programme, Abstracts, and Contributions. International Atomic Energy Agency IAEA. 2014. p. EX/P5-24