The DTT device: System for heating

The proposed Divertor Test Tokamak, DTT, aims at studying power exhaust and divertor load in an integrated plasma scenario. Additional heating systems have the task to provide heating to reach a reactor relevant power flow in the SOL and guarantee the necessary PSEP/R together with adequate plasma performances. About 40 MW of heating power are foreseen to have PSEP/R ≥ 15 MW/m. A mix of the three heating systems has been chosen, assuring the necessary flexibility in scenario development. An ECRH system at 170 GHz will provide 10 MW at plasma for several tasks, such as: bulk electron heating, localized CD, avoidance of impurity accumulation and MHD control. In addition 15 MW of ICRH in the range 60–90 MHz will provide the remaining bulk plasma heating power, on both electrons and ions. ICRH, in minority scheme, will produce fast ions, allowing the study of fast particle driven instabilities like alphas in D-T burning plasmas. The heating schemes foreseen in DTT are 3He and H minority as well as Deuterium 2nd harmonic. The addition of 15 MW of NBI, later in the project, could provide a mainly parallel fast ion distribution to simulate the alpha heating scheme of a reactor. The NBI primary aim is to support plasma heating during the flat top phase when the need of central power deposition and the minimization of the shine-through risk suggests a beam energy around 300 keV. In the first phase of the DTT project the available power will be at least 25 MW, to be increased during the lifetime of the machine.