To assess the effect of edge neutrals on the low-to-high confinement transition threshold, a broad range of plasma discharges has been analysed. From this analysis, the transition power divided by the density, at constant magnetic field, appears to be a function of a single parameter measuring the neutrals' effect. This results suggest that there is a missing parameter linked to the neutrals in the power-threshold scaling laws.
Critical parameters for turbulent transport in the SOL: mechanism for the L - H transition and its impact on the H-mode power threshold and density limits