Lower hybrid wave (LHW) heating has been investigated in the HT-7superconducting tokamak. It has been observed that the plasma performance isobviously enhanced by LHW heating. The ion temperature was increased by0.4 keV and the electron temperature by 0.3 keV. Meanwhile the centralline-averaged electron density was increased from 1×1019 to2.6×1019 m-3. The high-energy ion tail produced by the LHWwas observed from the charge-exchange spectra measured by neutral particleanalysis. An ion heating efficiency of (2-3) ×1013 eV kW-1 cm-3 was obtained in the experiments. The evolution of theprofiles of ion temperature shows clearly an off-axis ion heating by LHW,which is in agreement with code simulations.
Mechanism of ion and electron LH heating on the FT-2 tokamak