Lhcd Experiments In High Performance Plasmas In Jet

Lower Hybrid Current Drive (LHCD) has been used for current profile shaping in the shear optimisation experiments in 1996/97 in JET. P(LH)less than or equal to 3MW has been applied in the initial current ramp-up in order to control the internal inductance. An internal transport barrier with improved central electron confinement has been produced in this phase with LHCD alone. This has resulted in a peaking of the electron temperature profile and T-e0 above 10keV at n(e0)less than or equal to 1.5 x 10(19) m(-3). The profile of the LH driven current, as determined by hard X-ray measurements, is peaked at approximately mid-radius in these conditions. Good coupling of the LH waves has been obtained by the use of a near gas feed. This method reduces the risk of plasma-launcher interaction. since the launcher can be positioned in the shadow of the poloidal limiters. A reflection coefficient of 5% has been maintained at a plasma-launcher distance of 8cm and P-LH=5MW has been coupled to divertor plasmas in L-mode with this method.