The JET-Enhanced Performance programme: More heating power and diagnostic capabilities in preparation for ITER

Since early 2000, the JET-Enhanced Performance (JET-EP) programme has been aiming at optimising JET for ITER-relevant plasma operations, from 2005 onwards. The overall heating capability of JET will be increased to 40MW by upgrading the neutral beam system and building a new ITER-like ion cyclotron radio-frequency heating (ICRH) antenna with particularly stringent specifications. The new divertor will be able to absorb more than 300MJ per shot and allow running high-triangularity ITER-like scenarios with a greater flexibility with respect to different plasma configurations. The control of extreme plasma shapes will be reinforced and a new disruption mitigation system using a very fast gas valve will be provided. The diagnostic capability will be enhanced by several new systems designed to address a number of crucial physical phenomena for ITER. To study tritium retention further, new technologically challenging erosion-redeposition diagnostics will be installed, particularly in the divertor region, both real time and integrating. New neutron detectors using the latest advances in scintillators and data recording techniques, detectors for fast α particles with high pitch angle and energy resolution, high-resolution Thomson scattering, with a 20Hz repetition rate, which will provide temperature and density profiles with a spatial accuracy close to 2cm are the leading items of this programme. New halo sensors will be installed to better understand disruption phenomena. New high-signal to noise bolometric tomography and an ambitious IR viewing system using a state of the art camera will also be added. This paper presents an overview, emphasising the main objectives and pointing out the various technological challenges and innovations.