Particle confinement of lower hybrid current driven plasmas and electron cyclotron heated plasmas in the WT-3 tokamak

Confinement properties of lower hybrid current driven (LHCD) plasmas and electron cyclotron heated (ECH) plasmas in the WT-3 tokamak are studied. The outward particle and energy fluxes are estimated from parameters of the scrape-off layer (SOL) plasma. During the LHCD period the density and temperature of the SOL plasma decrease drastically, while the density of the core plasma increases, suggesting a decrease of the outward flux. These results show that particle confinement is improved by LHCD. On the contrary, during ECH the density of the SOL plasma increases and the density of the core plasma decreases, suggesting a deterioration of particle confinement. Improved confinement is not obtained near the density limit of LHCD; the improvement is not related with MHD activities during LHCD.