The JET Technical and Scientific Performance and Future Plans by the JET Team

Three years have passed since the Joint European Torus (JET) started operation in June 1983. Phase I of the scientific programme, devoted to ohmic heating studies, has been completed. Phase II, devoted to additional heating studies started in January 1985. From the technical point of view JET has been entirely successful: indeed the plasma current, an important figure of merit for a tokamak, has reached 5.1 MA for 3s, (exceeding the design value of 4.8 MA). Ion Cyclotron Resonance Heating has added up to 6 MW to the plasma and Neutral Beam Injection has added up to 10 MW. The energy confinement time in ohmic discharges has reached 0.8s; but degradation has been observed with additional heating. Recently, combined heating (P_add up to 14.5 MW) allowed achievement of ion and electron temperatures of −7.5 keV at densities of ∼3 − 10¹⁹ m⁻³. Several proposals for improvements of the JET scientific performance are reported in the paper and summarised in the new development programme.