High ion temperature discharge and its long sustainment in both limiter and single null configurations on TRIAM-1M

A high ion temperature discharge in the lower hybrid current drive scheme has been obtained for the first time in the world in the TRIAM-1M superconducting tokamak. The high ion temperature mode is triggered by a transition which occurs within an operation window for the density, horizontal plasma position and antenna phasing. A steep ion temperature gradient (>80 keV/m) is formed near the core region at the transition. Long duration operation of this discharge has been successfully demonstrated in both the limiter and single null configurations by multiple control techniques.