Non-dimensional transport study on ELMy H-mode plasmas in JT-60U

Non-dimensional transport studies have been carried out for NBI heated ELMy H-mode plasmas in JT-60U. In a high-δ (triangularity) case, both the electron thermal diffusivity, X e , and the ion thermal diffusivity, X i , show gyroBohm-like diffusion, X e /X Bohm , X i /X Bohm (ρ * ) 0.7-0.9 , where ρ * is the normalized Larmor radius. The dependence of the energy confinement on the normalized collision frequency, ν * , was also studied. The weak ν * dependence of the energy confinement time, τ E /τ Bohm (1/ν * ) ∼0.3 , was also obtained in the high-δ case, On the assumption of the same ν * dependence of τ E /τ Bohm , the ρ * dependence of X * in the low-δ case is compatible with the high-δ case. When the ELM activity is strong enough to affect the global energy confinement, however, the ion energy confinement was significantly degraded, although the electron energy confinement still follows the gyroBohm-like diffusion.