The JET programme in support of ITER

The mid-term experimental programme of the JET tokamak exploits its recently enhanced scientific capabilities (e.g., new divertor allowing high-triangularity ITER-relevant scenarios, several new diagnostics) to address critical issues potentially impacting the detailed design of ITER components (e.g., first wall, heating and current drive systems, diagnostics) and, in parallel, further develop ITER-operating scenarios and address specific physics issues of direct relevance to ITER (e.g., transport physics, burning plasma physics). For the longer term, activities on a “JET programme in support of ITER” have been launched, aiming at making optimal use of JETʹs unique features: large plasma size and capability to handle beryllium and tritium. A full replacement of the first wall materials is planned (beryllium in the main wall and tungsten in the divertor). This should deliver answers to urgent plasma surface interaction questions, such as tritium retention, and provide operational experience in steady and transient conditions with ITER wall materials under relevant geometry and relevant plasma conditions. In addition, the JET auxiliary heating power will be upgraded to ∼45 MW, allowing access to ITER-relevant disruption and edge localised modes energy loss densities. This will open access to conditions of melt layer formation both on the beryllium first wall and the tungsten divertor and, on the other hand, help progressing, in particular, hybrid and advanced scenarios for ITER, which require full or partial current profile control, thereby making use of new dedicated diagnostics.