High power heating of a lower hybrid wave (LHW) was performed (PLHW ∼ 800 kW at 2.45 GHz) recently in the HT-7 tokamak. Lower hybrid current drive (LHCD) efficiency is studied for different injected powers and for different densities. Improved particle confinement is observed by the application of LHCD as characterized by an increase in the central line averaged electron density and the decrease in Dα emission. The particle confinement time (τp) increased by about 1.5 times. The dependence of energy confinement time (τE) on plasma density and LHW power is experimentally studied in detail.
On lower hybrid current drive in high magnetic field fusion reactor level tokamaks