Profile control experiments in jet using off-axis lower hybrid current drive

摘要

On lower hybrid current drive(LHCD)experiments in JET, up to 7.3 MW of lower hybrid(LH)power has been coupled to X point plasma, resulting in sawtooth suppression and full current drive up to 3 MA. The current drive efficiency reachedη_CD = 2.6×10~20 m~-2. A/W in these experiments. The LH power deposition and driven and driven current profiles can be quite well reproduced with the ray tracing and Fokker-Planck code in JET, even when multipass absorption of the LH wave is dominant. Profile control with off-axis LHCD has been used for increasing q above 1, thereby suppressing sawteeth before the edge localized mode(ELM)-free hot ion H mode.