Physics basis for the Divertor Tokamak Test (DTT) facility

This paper summarizes the physics basis of the Divertor Tokamak Test facility (DTT) under construction in Frascati,Italy, the target core plasma scenarios of the device and the current status of the research plan. DTT is a superconducting tokamak with 6 T on-axis maximum toroidal magnetic field, carrying plasma current up to 5.5 MA in pulses with total length up to 100 s. DTT has major radius R=2.19 m, minor radius a=0.70. The auxiliary heatingpower coupled to the plasma at maximum performance is 45 MW, provided by a mixture of ECRH, ICRH and by a 510 keV NIB. This allows matching the P_SEP/R values (where P_SEP is the power crossing the separatrix) with those of ITER and DEMO. The primary mission of DTT is to accelerate reaching the goal of fusion electricity with the study of plasma exhaust and of tokamak divertor in conditions relevant to ITER and DEMO and in regimes where highperformance plasma core and large Scrape Off Layer energy (SOL) flux will have to coexist. In addition, DTT willprovide a facility for fusion relevant tokamak physics and to address core confinement and stability issues in a varietyof plasma configurations, including negative triangularity scenarios, and the management of transient events like disruptions and ELM.