Status of JET

The aims are to study plasmas with parameters close to those required in a fusion reactor and in particular to operate eventually in a deuterium-tritium gas mixture and so to demonstrate significant α-particle heating of the plasma. The machine is physically large with a major plasma radius of 3m and minor radius of 1.2m. It has already been operated with the rated plasma current of 5MA at the full design level of toroidal field (3.4T). Pulse-lengths in this machine are measured in seconds, with a typical flat-top time at 4MA of 5s. After some planned changes to the poloidal field system and to the vacuum vessel supports it is expected that the current level will be raised to, or near, 7MA. The comprehensive list of diagnostics on the machine is outlined and discussed. At present about 7 Mbytes of data is acquired on each shot and this will rise further as new diagnostics come into operation. Two techniques are used to heat the plasma. Ion cyclotron resonance heating is planned to increase from the present 6MW level to an eventual 16-20MW. Neutral injection heating will also be increased from the present 3.5MW to 10-15MW. Neutral injection heating experiments started in January 1986. The latest results with neutral injection and combined neutral injection and ICRH are presented. The plans for the further exploitation are described. These include various measures aimed at improving the plasma purity, increasing the density limit and reducing or eliminating the confinement degradation