Isotope identity experiments in JET-ILW with H and D L-mode plasmas

JET Contributors, D. R. Hatch, C. F. Maggi, T. Ahlgren, L. Aho-Mantila, M. Airila, C. Björkas, K. Heinola, A. Lahtinen, K. Nordlund, E. Safi, S.-P. Pehkonen, A. Salmi, T. Tala

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NBI-heated L-mode plasmas have been obtained in JET with the Be/W ITER-like wall (JET-ILW) in H and D, with matched profiles of the dimensionless plasma parameters, rho*, nu*, beta and q in the plasma core confinement region and same T-i/T-e and Z(eff). The achieved isotope identity indicates that the confinement scale invariance principle is satisfied in the core confinement region of these plasmas, where the dominant instabilities are Ion Temperature Gradient (ITG) modes. The dimensionless thermal energy confinement time, Omega(i) tau(E,th), and the scaled core plasma heat diffusivity, A chi(eff)/B-T, are identical in H and D within error bars, indicating lack of isotope mass dependence of the dimensionless L-mode thermal energy confinement time in JET-ILW. Predictive flux driven simulations with JETTO-TGLF of the H and D identity pair is in very good agreement with experiment for both isotopes: the stiff core heat transport, typical of JET-ILW NBI heated L-modes, overcomes the local gyro-Bohm scaling of gradient-driven TGLF, explaining the lack of isotope mass dependence in the confinement region of these plasmas. The effect of E x B shearing on the predicted heat and particle transport channels is found to be negligible for these low beta and low momentum input plasmas.

Original languageEnglish
Article number076028
JournalNuclear Fusion
Issue number7
Number of pages11
Publication statusPublished - Jul 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 114 Physical sciences

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