Self-consistent spatiotemporal modeling of the interactions between full-energy helium ions and a drift wave-zonal flow system

Abstract This paper develops a self-consistent one-dimensional (1D) spatiotemporal model to investigate the interactions between full-energy helium (He) ions and drift wave–zonal flow (DW–ZF) system. The model integrates three physical components: (1) the interactions between He ions and the DW–ZF system, wherein the dilution of He ions modulates DW–ZF dynamics and in turn DW-driven transport simultaneously alters the profile of the He ion dilution factor; (2) the explicit inclusion of dilution effects on the growth rate in addition to the real frequency of DW; and (3) a turbulence spreading term added into the evolution equation of DW. Numerical results reveal that compared with the case with a fixed dilution profile and constant linear growth rate of DW, evolving He ion dilution factor and considering the corresponding dilution-modified linear growth rate in the self-consistent 1D model decreases the saturated value of He ion dilution factor—especially the contribution from lower energy He ash, increases the DW energy, decreases and even causing a reversal radial profile of ZF energy. These findings show that He ash removal may be more achievable even though the increase in the DW energy indicates that the improvement of plasma confinement might not be as substantial as the prediction with fixed dilution factor. Moreover, analytical expressions for the saturated He ion dilution factor, DW energy and ZF energy under a zero-dimensional local approximation are derived, which can qualitatively explain the corresponding 1D results. Overall, these findings highlight the importance of self-consistent modeling for reliably assessing He ash accumulation and confinement performance in future burning plasmas.