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

The control of the current profile near the magnetic axis by electron cyclo tron current drive (ECCD) is demonstrated experimentally on the WT-3 tokama k. Compared with the previous experiments, the driven current was increased by injecting the elliptically polarized microwave with the optimal polariz ation ellipticity. The effect of the improved absorption appears on the saw teeth 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 discus sed. (C) 2001 Published by Elsevier Science B.V.