Gas puff modulation experiments on JT-60U

Density and temperature modulations were induced in JT-60U plasmas using sinusoidal modulation of gas puff injection. From an analysis of the density modulation, the particle diffusion coefficients were evaluated to be 0.2 m 2 /s in the central region and 0.8 m 2 /s in the edge region of ohmically heated plasmas. Furthermore, from an analysis of the electron temperature modulation, the ratio of the heat and particle diffusion coefficients, χ e /D, was estimated to be between 5 and 10