In the Large Helical Device (LHD), upgrading of the key hardware system since the last EPS conference has led to (1) higher Te (Te(0) = 4.4 keV at 〈ne〉 = 5.3×1018 m-3 and Pabs = 1.8 MW); (2) higher confinement (τE = 0.3 s, Te(0) = 1.1 keV at 〈ne〉 = 6.5×1019 m-3 and Pabs = 2.0 MW); (3) higher stored energy Wpdia = 880 kJ; and (4) the highest β value in helical devices (2.4% at B = 1.3 T). The energy confinement was systematically higher than that predicted by the International Stellarator Scaling 95 up to a factor of 1.6. Ion cyclotron range of frequencies (ICRF) power up to 1.3 MW was reliably injected into the plasma without significant impurity contamination and a plasma with stored energy of 200 kJ was sustained for 5 s by ICRF alone. Long pulse discharges greater than 1 min in duration have been successfully achieved with ICRF power alone and with neutral beam injection (NBI) power alone. With NBI heating an 80 s discharge was achieved with a heating power of 0.5 MW at 2.75 T. The electron density was maintained at around 1.6×1019 m-3 by controlled gas puffing. The central electron and ion temperatures were kept around 1.5 keV. With ICRF heating, a similar long pulse discharge was achieved for 68 s with a heating power of 0.85 MW. The sustained plasma parameters are: Wp approximately 110 kJ, Te(0) approximately Ti(0) = 2.0 keV and 〈ne〉 = 1.0×1019 m-3. During these discharges, no increase in radiation power has been observed.
|ジャーナル||Plasma Physics and Controlled Fusion|
|号||12 SUPPL. B|
|出版ステータス||出版済み - 12月 2000|
|イベント||27th European Physical Society Conference on Controlled Fusion and Plasma Physics - Budapest, Hung|
継続期間: 6月 12 2000 → 6月 16 2000
!!!All Science Journal Classification (ASJC) codes