Design and development of plasma diagnostics to tackle the Divertor Tokamak Test research objectives (invited)

The Divertor Tokamak Test (DTT) is a compact sized (R = 2.19 m, a = 0.70 m) fully superconducting tokamak presently under construction at the ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) research center in Frascati, Italy. With its high field (B = 5.85 T) and plasma current (Ip = 5.5 MA), actively cooled in-vessel W components to sustain long pulse duration (tpulse = 100 s), and a significant amount of external heating power (up to P = 45 MW to the plasma), it aims at exploring heat exhaust solutions in fusion-relevant environments by reproducing the level of divertor heat loads expected in ITER and DEMO. Recently, a first version of the DTT research plan was released, defining the project objectives and describing targeted plasma scenarios. The research plan also sets the basis for the development of diagnostic systems, closely following the experimental phases of the machine therein described, with a particular focus toward the divertor region. Since DTT's first plasma will soon be followed by an experimental phase, operations will start with a full set of systems for machine protection and plasma control, as well as diagnostics to probe initial scenarios. Advanced systems for the investigation of the physics of transport and fast particles will be developed and installed as the machine performance evolves, following its power upgrades. This paper gives an overview of the DTT tokamak targeted diagnostic set, focusing on how these systems are designed to address the scientific goals of the project from first plasma to full power scenarios, and providing context for further publications dedicated to specific diagnostic systems.