GAS PUFF MODULATION EXPERIMENTS ON JT-60U

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