MHD Analysis on the Physics Design of CFETR Baseline Scenarios

The China Fusion Engineering Test Reactor (CFETR), currently under intensive physics and engineering designs in China, is a major project representative of the low-density steady-state pathway to the controlled fusion energy. One of the primary tasks of the physics design for CFETR is the assessment and analysis of the magnetohydrodynamic (MHD) stability of the proposed design schemes. Comprehensive MHD stability assessment of the CFETR baseline scenarios have led to preliminary progress that may further benefit engineering designs. For CFETR, the electron cyclotron current drive (ECCD) power and current required for the full stabilization of neoclassical tearing mode (NTM) have been predicted in this work, as well as the corresponding controlled magnetic island width. A thorough investigation on resistive wall mode (RWM) stability for CFETR is performed. For 80% of the steady state operation scenarios, active control methods may be required for RWM stabilization. The process of disruption mitigation with massive neon injection on CFETR is simulated. The time scale of and consequences of plasma disruption on CFETR are estimated, which are found equivalent to International Thermonuclear Experimental Reactor (ITER). Major MHD instabilities such as NTM and RWM remain challenge to steady state tokamak operation. On this basis, next steps on CFETR MHD study are planned on NTM, RWM, and shattered pellet injection (SPI) disruption mitigation.