On the feasibility of $\mathbf{T_i}$ collisional heating and $\mathbf{T_e/T_i}$ control on DEMO using ECRH

We explore the physical feasibility of a DEMO1 scenario supplied uniquely with Electron Cyclotron Resonant Heating (ECRH) as the external heating and current-drive system. Specifically, we study the ability of ECRH to collisionally heat a deuterium-tritium mixture from L-mode to H-mode, while controlling the $T_e/T_i$ ratio, crucial for the onset of ITG turbulent transport. Simulations with the ASTRA code [1] employing the TGLF code [2] as the turbulent transport model, are used to assess the kinetic profile temporal evolution of such a DEMO1 discharge. Boundary conditions at the plasma edge are applied to model the transition from the initial L-mode to H-mode flat top, including the treatment of the H-mode pedestal. Numerical scans over the position and width of the ECRH deposition layer, ECRH available power and plasma density Greenwald fraction are performed. For each scan, a power balance analysis is made with regards to collisional heating from electrons to ions, electron and ion heat fluxes and $T_e/T_i$ ratio temporal evolution. The results and conclusions drawn from such scans will be presented at the conference.\\ \, [1] G. V. Pereverzev et al. Tech. rep. 5/98. Max-Planck-Institut fur Plasmaphysik, 2002.\\ \, [2] G. M. Staebler et al., In: Physics of Plasmas 12.10 (2005)