Birkenmeier, G.Solano, E. R.Carvalho, I. S.Hillesheim, J. C.Delabie, E.Lerche, E.Taylor, D.Gallart, D.Mantsinen, M. J.Silva, C.Angioni, C.Ryter, F.Carvalho, P.Fontana, M.Pawelec, E.Silburn, S. A.Siren, P.Aleiferis, S.Bernardo, J.Boboc, A.Douai, D.Puglia, P.Jacquet, P.Litherland-Smith, E.Jepu, IKos, D.Sun, H. J.Shaw, A.King, D.Viola, B.Henriques, R.Kirov, K. K.Baruzzo, M.Garcia, J.Hakola, A.Huber, A.Joffrin, E.Keeling, D.Kappatou, A.Lennholm, M.Lomas, P.de la Luna, E.Maggi, C. F.Mailloux, J.Maslov, M.Rimini, F. G.Vianello, N.Verdoolaege, G.Weisen, H.Wischmeier, M.2023-04-242023-04-242023-04-242023-05-0110.1088/1361-6587/acc423https://infoscience.epfl.ch/handle/20.500.14299/197148WOS:000958694700001The required heating power, P-LH, 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. PLH, 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-LH is not the same in plasmas with the same effective isotope mass, A(eff), when they differ in their isotope composition. Thus, A(eff) is not sufficient to describe the isotope effect of P-LH 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-LH, and an effective heat diffusivity, ?(eff), 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-LH.Physics, Fluids & PlasmasPhysicsl-h transitiond-t plasma operationisotope effectstransportisotope mixturestritium plasmasregimetext::journal::journal article::research article