Simulation analysis of ICRF heating scenarios for CFEDR

As a critical ion heating technique for future fusion reactors, Ion Cyclotron Range of Frequencies (ICRF) heating is an important auxiliary heating method. The China Fusion Engineering Demo Reactor (CFEDR) plans to inject 20\,MW of ICRF power into the plasma for sustaining H-mode operation. In this study, two candidate minority heating schemes, ³He minority heating (60\,MHz) and H minority heating (90\,MHz), are considered. Power deposition simulations have been carried out by using the TOMCAT code, including optimization of the minority ion concentration (XMI), toroidal mode number (Nₜₒᵣ), and RF frequency (fICRF) of both heating schemes. The primary goal is to maximize the ion absorption ratio, and minimize electron absorption, thereby ensuring efficient core heating for CFEDR operation. It is shown that in the cases of X[³He] = 2% and X[H] = 4%, Nₜₒᵣ = 40 and fICRF = 60\,MHz for ³He minority heating (fICRF = 90\,MHz for H minority heating), maximum power absorption can be achieved with the two main minority heating scenarios, in which ion absorption ratios exceed 70% for ³He minority heating and 85% for H minority heating, respectively. During the plasma current ramp-up phase, RF power deposition on the minorities of ³He is about 54% -- 74% and H is around 62% -- 85% with off-axis heating. In the flat-top phase, RF power is absorbed predominantly by ions and is on-axis heating. This study aims to optimize ICRF heating scenarios by maximizing ion absorption and ensuring central power deposition while minimizing electron damping losses.