Investigation of Development of Density Profiles in Start-Up Phase of DEMO and Fueling/Heating Scenario Using TASK/TR Code

Abstract This study has investigated the effect of particle transport of fuel ions, deuterium (D) and tritium (T), and helium ash (He) as well as their heat transport on the nuclear fusion output in a DEMO reactor. The result was assessed and possible start-up scenarios for DEMO was discussed. In the study, the integrated tokamak modeling code, TASK/TR is used to investigate the impact of the neutral beam injection (NBI) fuel source on the plasma density distribution. It was found that, due to the dilution from burn-up and helium ash, the fuel density profile becomes either flat or hollow in the core region when fuel is supplied only from the periphery. The reduction of core fuel dilution by NBI is discussed in the context of the results, highlighting the potential of NBI to mitigate the hollow density profile and enhance the central fueling during startup.