INNOVATIONS IN THE LHD DIVERTOR PROGRAM

Various innovative divertor concepts have been developed to improve th e LHD plasma performance. They are two divertor magnetic geometries (h elical divertor configurations with and without n/m = 1/1 island) and two operational scenarios (confinement improvement by generating high temperature divertor plasma and simultaneous achievement of radiative cooling and H-mode-like confinement improvement). In addition, technol ogical development of new efficient hydrogen pumping schemes are being pursued for enhancing the divertor control capability.