On-axis electron cyclotron current drive experiment on WT-3

The control of the current profile near the magnetic axis by electron cyclotron current drive (ECCD) is demonstrated experimentally on the WT-3 tokamak. Compared with the previous experiments, the driven current was increased by injecting the elliptically polarized microwave with the optimal polarization ellipticity. The effect of the improved absorption appears on the sawteeth behavior, soft X-ray emissivity and so on. The difference of the time evolution of the loop voltages between co-CD and counter-CD is also discussed.