Extensive studies of a steady-state tokamak reactor have been carried out on the superconducting tokamak TRIAM-1M. A discharge of n̄e = 2 × 1018 m-3 lasting more than 2 h has been demonstrated using a 2.45 GHz lower hybrid current drive (LHCD). A high-density plasma of n̄e = 2 × 1019 m-3 has been sustained for 1 min using a 8.2 GHz LHCD under the high average wall loading of 5 MW m-2 on the limiter. Recently, a single-null divertor configuration with high elongation (κ = 1.5) was also successfully maintained for 1 min by the 2.45 GHz LHCD. A transition of the ion temperature (Ti) from 0.6 keV to about 2.5 keV is observed in 2.45 GHz LHCD plasmas; this operational regime is called the 'high ion temperature (HIT)' mode. The 'HIT' mode is characterized by the existence of a steep Ti gradient (≈50 keV m-1) near r/a ∼ 0.4. It is found that the 'HIT' mode appears in a narrow window of the electron density and horizontal plasma position. The 'HIT' mode can be successfully maintained for over 1 min with accurate control of the density and position.
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Condensed Matter Physics