Multi-time-scale coupled simulations on the CFC target erosion process with helium plasma on HIT-PSI device

Understanding the coupled evolution of surface erosion, impurity transport, heat transfer and surface morphology under high-flux plasma irradiation remains an important challenge in plasma–material interaction modelling. To address this research gap, a multi-physics coupling physical model incorporating the near-wall particle transport, the wall erosion, the temperature field response, and the surface morphology evolution was constructed, and a corresponding simulation code was developed. The proposed model integrates a two-dimensional continuous morphology model, a macroparticle transport model, a Bohdansky–Yamamura physical sputtering model, and a three-dimensional continuum heat conduction model, achieving self-consistent multi-physics coupling across multiple time scales. Based on this, simulations were conducted to investigate the helium plasma irradiation experiments on carbon fiber composite (CFC) materials under a heat flux density of 20.4 MW/m2 in the superconducting linear plasma generating device HIT-PSI. The simulation results indicate that the maximum erosion depth reaches 32.1 µm and the core-region sputtering yield is 5.13×10−4 after 20 min of irradiation. The calculated erosion pattern and sputtering yield show semi-quantitative consistency with the experimental surface-height variation and net sputtering yield. The established model captures the principal characteristics of macroscopic erosion evolution and physical sputtering/redeposition behaviors within the assumptions and applicability range of the present model.