Ultra-long pulse operation (> 3 min) was achieved on the superconducting high field tokamak TRIAM-1M. In this operation, the plasma current was maintained with a relatively peaked current distribution by the 2.45 GHz radiofrequency power (PRF ≤ 35 kW) alone. A stationary plasma with a driven current of up to 35 kA and a line averaged electron density of up to 3 × 1012 cm−3 was produced by precise plasma position and gas feed control. The extremely long discharge showed the interesting characteristics that the high temperatures of about 1 keV for the electrons and about 0.5 keV for the ions were kept almost constant during steady state current drive and that there was no impurity accumulation which could have a fatally adverse effect on steady state tokamak operation.
超長パルス運転（> 3 min）が超伝導高磁場トカマクTRIAM-1Mにおいて達成された。この運転では、プラズマ電流は、2.45 GHzの高周波電力（P_RF ≤ 35 kW）のみによって、比較的ピークした電流分布を保ちながら維持された。駆動電流が最大35 kA、線平均電子密度が最大3 × 10¹² cm⁻³の定常プラズマが、精密なプラズマ位置およびガス供給制御によって生成された。この極めて長い放電は、定常状態の電流駆動中に、電子で約1 keV、イオンで約0.5 keVの高温がほぼ一定に保たれ、また、定常状態のトカマク運転に致命的な悪影響を及ぼし得る不純物の蓄積がなかったという興味深い特性を示した。