High power heating and current drive in JT-60

Advances of JT-60 experiments in current drive and high power heating are presented. Fully noninductive current drive of 2 MA is achieved by LHRF without OH assistance. The current drive efficiency η CD , defined as n-bar e (10 19 m -3 )I RF (MA)R p (m)/P LH (MW), is in the range 0.8 - 1.7 and is improved to 1.7 - 3.0 when NB heating is applied to the LHCD plasma. Confinement improvement is also obtained when LHCD and NB heating are combined. The MHD fluctuations in the central plasma region of such a discharge are suppressed by a factor of 10 compared to the case of NB heating only. In the electron heating mode of LHRF, T e (0) of 6±1 keV is obtained with a high heating efficiency of 2- 3 × 10 19 keV/MWm 3 , and L-mode-like behavior is seen in the energy confinement in such plasmas. High ion temperatures of T i (O) = 11 ± 2 keV are attained in hydrogen plasmas at densities of n-bar e = 2 - 3 × 10 19 /m 3 with NB heating. Substantial beam acceleration is observed when NB and ICRF heating are combined. Charge exchange neutral spectra show that high energy ion tail of up to at least 160 keV is generated compared to the NB acceleration voltage of 60 kV.