A study of mid-harmonic ion cyclotron range of frequencies heating and current drive on the HL-3 tokamak

BackgroundIon Cyclotron Resonance Heating (ICRH) serves as a critical auxiliary heating method for high-performance operation in tokamaks. The HL-3 device is planning a 6 MW ICRH system in its next-phase upgrade in which the fast waves in the mid-harmonic ion cyclotron frequency range show significant application potential for this reactor-grade tokamaks.PurposeThis study aims to investigate wave propagation and absorption characteristics under quadruple frequency (4ΩD) based on high-parameter steady-state operation scenario on the HL-3 device.MethodsTheoretical analysis of wave damping coefficients for electrons and ions in the D(H) heating scheme under 4ΩD conditions was conducted on the basis of fast wave dispersion function. Wave propagation and absorption characteristics of ICRH under high parameter steady-state operation mode of HL-3 were investigated through AORSA full-wave simulations.ResultsAnalysis results show that electron damping dominates wave absorption at 4ΩD whilst the introducing hydrogen (H) minority ions substantially enhances ion damping coefficients. Full-wave simulations demonstrate that when hydrogen concentration XH exceeds 5%, total ion power absorption slightly surpasses electron absorption, with H ions dominating the ion absorption share. Comparative analysis of D(H), D(3He), and Neutral Beam Injection (NBI) synergistic heating schemes indicates that H minority ions and energetic deuterium (D) ions effectively improve ion heating efficiency whereas helium-3 (3He) proves more favorable for current drive.ConclusionsResults of this study indicate that significant electron heating can be achieved under 4ΩD. The introduction of a small amount of H ions or energetic D ions into the D majority ions significantly enhances ion heating efficiency, and higher driven current is yielded by introducing 3He.