The experimental results from the Large Helical Device (LHD) heliotron / torsatron of the first two years are reviewed. The world's largest superconducting helical coils have been driven up to 2.9 Tesla on the axis which is close to the designed value (3 T). The obtained plasma performances are better than those predicted by the database from the medium-size helical devices. These improvements are attributed mainly to the optimization of a magnetic field configuration which can be controlled by shifting the magnetic axis inward than that of standard case. This configuration improves particle orbits of trapped high energy ions resulting in success of ICRF heating in LHD. Efforts have also been made on steady state plasma operation, and long pulse discharges more than one minute have been achieved both by ICRF and NBI. It should be noted that the feature of no current-disruption in helical plasma makes the discharges easy.
All Science Journal Classification (ASJC) codes
- General Engineering