The role of isotope mass and transport for H-mode access in tritium containing plasmas at JET with ITER-like wall

G. Birkenmeier (Corresponding Author), E. R. Solano, I. S. Carvalho, J. C. Hillesheim, E. Delabie, E. Lerche, D. Taylor, D. Gallart, M. J. Mantsinen, C. Silva, C. Angioni, F. Ryter, P. Carvalho, M. Fontana, E. Pawelec, S. A. Silburn, P. Sirén, S. Aleiferis, J. Bernardo, A. BobocD. Douai, P. Puglia, P. Jacquet, E. Litherland-Smith, I. Jepu, D. Kos, H. J. Sun, A. Shaw, D. King, B. Viola, R. Henriques, K. K. Kirov, M. Baruzzo, J. Garcia, A. Hakola, A. Huber, E. Joffrin, D. Keeling, A. Kappatou, M. Lennholm, P. Lomas, E. de la Luna, C. F. Maggi, J. Mailloux, M. Maslov, F. G. Rimini, N. Vianello, G. Verdoolaege, H. Weisen, M. Wischmeier, JET Contributors

Research output: Contribution to journalArticle in a proceedings journalScientificpeer-review

1 Citation (Scopus)

Abstract

The required heating power, P L H , to access the high confinement regime (H-mode) in tritium containing plasmas is investigated in JET with ITER-like wall at a toroidal magnetic field of B t = 1.8 T and a plasma current of I p = 1.7 MA. P L H , also referred to as the L-H power threshold, is determined in plasmas of pure tritium as well as mixtures of hydrogen with tritium (H-T) and mixtures of deuterium with tritium (D-T), and is compared to the L-H power threshold in plasmas of pure hydrogen and pure deuterium. It is found that, for otherwise constant parameters, P L H is not the same in plasmas with the same effective isotope mass, A e f f , when they differ in their isotope composition. Thus, A e f f is not sufficient to describe the isotope effect of P L H in a consistent manner for all considered isotopes and isotope mixtures. The electron temperature profiles measured at the L-H transition in the outer half of the radius are very similar for all isotopes and isotope mixtures, despite the fact that the L-H power threshold varies by a factor of about six. This finding, together with the observation of an offset linear relation between the L-H power threshold, P L H , and an effective heat diffusivity, χ e f f , indicates that the composition-dependent heat transport in the low confinement mode (L-mode) determines, how much power is needed to reach the necessary electron temperatures at the edge, and hence P L H .

Original languageEnglish
Article number054001
Number of pages10
JournalPlasma Physics and Controlled Fusion
Volume65
Issue number5
DOIs
Publication statusPublished - May 2023
MoE publication typeA4 Article in a conference publication
Event48th EPS Conference on Plasma Physics: Online - Virtual
Duration: 27 Jun 20221 Jul 2022

Keywords

  • D-T plasma operation
  • isotope effects
  • isotope mixtures
  • L-H transition
  • transport
  • tritium plasmas

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