ENERGY CONFINEMENT AND PLASMA HEATINti DURING LOWER HYBRID EXPERIMENTS IN FT

power up to 450 kW has been injected into the plasma of FT in the electron heating regime (n 5 5X1Ox3 ~m-~) producing electron and ion temperature increases of about I keV and .5 kef respectively without significant enhancement of Zeff. A density increase is observed due to an improvement of particle confinement time. An energy balance at intermediate power lev= 300 kW) is carried out for two different types of discharges, one without s awteeth E;e?%er with c awteeth. The balance shows that in order to account for the total injected power one has to assume equal electron thermal conductivity for the OH and the OH+RF phase. The energy confinement-time does not v ary from its ohmic value for both d ischarges. Finally an investigation, at n above the density limit, of the radial source of the fast ion tails and of the characteriestics of the Parametric Decay Instability is presented.