Lower hybrid current drive in FTU high density shear reversed discharges

Results are reported of the 8 GHz Lower Hybrid experiments on FTU after the installation of the new toroidal limiter. A figure of merit of the Current Drive efficiency eta(CD) approximate to 0.11.10(20) A/Wm(2) is estimated for plasma density <(n)over bar (e)> = 10(20) m(-3) and no appreciable broadening of the launched frequency is detected. In low density experiments sawteeth are stabilised and m = 1 activity is present in the plasma. Shear reversed discharges with large reversal radius, r(S)/a approximate to 0.5, are obtained at higher density, lower temperature, B-T = 4 T, q(a) approximate to 5.5, by off-axis LH CD. The reversed configurations exhibit high central temperature coexisting with regular m = 2, n = 1 relaxations of large amplitude and are maintained up to LH switch off. At higher magnetic field, B = 5.2 T, q(a) approximate to 7, irregular DTM crashes are present during the whole LH pulse. Confinement time of radiofrequency heated discharges (P-LH = 0.5 divided by 2.P-OH) exhibits the same behaviour of FTU ohmic discharges following the ITER89-P scaling. Preliminary results of central 140 GHz Electron Cyclotron Resonant Heating (ECRH) during the plasma current ramp-up, aimed at obtaining shear reversed configurations are also reported.