The hydrogen isotope effect on confinement is discussed by investigating the coupling between confinement, wall material and scrape-off-layer (SoL) turbulence. An emphasis is placed upon the dependence of the neutral density on the hydrogen mass number. The momentum loss via CX process in the barrier is studied, and its influence on the radial electric field in the barrier (so as to modify the suppression of transport) is discussed. The penetration of slow neutrals and the reflection of fast neutrals on the wall are considered. Combining these processes, the influence of hydrogen mass number on the atomic, molecular, material and plasma interactions is investigated. The penetration of strong fluctuations in the SoL plasma into the confined plasma via the fuelling of neutral particles (i.e. fuelling fuels turbulence) is also discussed. The hydrogen isotope effect on this source of edge turbulence, which can affect the core-confinement, is discussed.
Isotope effects on transport in LHD