RF heating and current drive in TORE SUPRA

Recent lower hybrid and ion cyclotron heating experiments are reported with emphasis on phenomena related to profile control and having stationary potentialities. Long pulse operation (67 s, 1 MA) has been very successful, with an equivalent of 41 Wb saved. Flux consumption during current ramp-up is investigated, and a scaling based on 1-D theory is given and compared with experimental results. The existence of a stationary, enhanced performance regime (LHEP) with improved confinement and reduced magnetic shear inside a high temperature gradient zone (q0 approx. 1.2, Te0 approx. 8-10 keV) has been found, showing complete decoupling between the electron temperature and the current density profiles. The beneficial effect of boron carbide coating on the ICRH Faraday screens is assessed, and the duration of sawtooth free periods is increased and has reached 830 ms during combined ICRH/LH operation. (author). 10 refs, 4 figs