Study of density fluctuation during low hybrid current drive on HT-7 tokamak

An experimental study of medium and high-k density fluctuations has been performed during low hybrid current drive (LHCD) in the HT-7 tokamak. Two series of plasma discharges in different plasma current with a limiter configuration were conducted in which the injected LHW power was gradually increased. The fluctuation level of the mode in channel kθ=12 cm−1 and kθ=20 cm−1 is related to the q profile, and the normalized frequency spectrum is found to be independent of the LHW power.