M. Nagata, T. Hanao, H. Hirono, T. Hyobu, M. Ishihara, K. Ito, T. Nakayama, K. Matsumoto, Y. Kikuchi, N. Fukumoto
39th EPS Conference on Plasma Physics 2012, EPS 2012 and the 16th International Congress on Plasma Physics 2012年12月1日
The dynamo current drive with two-fluid effects has been investigated in the helicity-driven spherical torus (ST) plasmas on HIST. 2D internal magnetic field measurements of the ST configuration has verified the flux amplification and the generation of the closed flux during the coaxial helicity injection (CHI). We have found that not only MHD 〈δv×δB〉|| dynamo but also Hall 〈δj×δB〉||/en dynamo plays an important role in the helicity transport for the current sustainment. Hall-MHD induced-electric fields satisfy the parallel mean-field Ohm's law balance. We have also observed transverse propagation and damping of a low-frequency Alfven wave. The dynamo activities for the current drive may be caused by the Alfven waves.