Energy confinement of hydrogen and deuterium H-mode plasmas in JT-60U

Abstract

Energy confinement properties for hydrogen and deuterium H-mode plasmas are investigated. The thermal energy confinement time becomes longer in deuterium by a factor of ∼1.4 than in hydrogen at a given absorbed power. When the absorbed power is fixed, the values of electron temperature Te and ion temperature Ti become explicitly higher in deuterium than in hydrogen across the whole range of minor radius while the profiles of electron density ne are almost the same. Accordingly, the effective heat diffusivity becomes relatively lower in deuterium than in hydrogen. Despite almost the same power crossing the separatrix, type-I ELM frequency for hydrogen becomes approximately double that of deuterium. When the stored energy is fixed, the spatial profiles of ne, Te and Ti become identical for both cases while higher heating power is required in the hydrogen case. The pedestal pressure is about twice as high in deuterium as that in hydrogen at a given absorbed power. The increase of the pedestal temperature is more significant for the deuterium case while the pedestal density is not changed. The poloidal beta at the H-mode pedestal is increased linearly with the increased total poloidal beta for both cases. The relation between and is almost identical regardless of the difference of the isotope species.