Internal Transport Barriers in JET Deuterium-Tritium Plasmas

The observation of internal transport barriers (ITBs) in which ion thermal diffusivity is reduced to a neoclassical level has been made for the first time in tokamak plasmas fueled with deuterium and tritium ions using a broad current density profile. The heating and current profiles required to obtain an ITB are similar in D-T and D-D plasmas. Central ion temperatures of 40 keV and plasma pressure gradients of ${10}^{6}\mathrm{Pa}/\mathrm{m}$ were observed in a D-T plasma, leading to a fusion triple product ${n}_{i}{T}_{i}{\ensuremath{\tau}}_{E}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.10}^{21}{\mathrm{m}}^{\ensuremath{-}3}\mathrm{keV}\mathrm{s}$ and 8.2 MW of fusion power. There is potential for further optimization as a step towards the development of efficient tokamak fusion reactors.