August 8, 2024
On the road to commercializing fusion, privately-funded TAE Technologies has produced steady-state plasmas in field-reversed configurations suitable for advanced reactors. These have the highest possible plasma pressure with a modest applied magnetic field, opening the possibility for advanced fuel cycles. An essential feature of TAE’s reactor design is the injection of energetic ions using neutral beams, a type of compact particle accelerator, to provide heating and drive plasma current by injecting energetic ions. The relative energy content of these “fast ions” exceeds that of other, more–studied plasma systems. This project will extend the understanding of the interaction of these fast ions with the background plasma. As a large part of the energy released by fusion is in the form of fast alpha particles, the understanding and control of fast particle physics is essential for a reactor to succeed. As is the case in tokamaks, TAE’s plasmas exhibit bursts of oscillations associated with fast particles, and also show evidence that there is more than expected transfer of energy from the fast ions to the background plasma, which effect has been noted to be useful for improving reactor operation by increasing reactivity. In addition to the excellent and improving diagnostics of the experimental observations, it is essential to understand these physics theoretically, and some preliminary computational work has found modes with similar characteristics. In spite of this progress, agreement between theory and experiment is notably lacking. In particular, the computations show destructive modes which grow to uncontrollable size, while experimentally similar modes remain small and have benign or even beneficial effects. To resolve this dichotomy, TAE is teaming with Princeton Plasma Physics Laboratory (PPPL) to make use of their theory expertise and advanced, well-benchmarked computer codes to investigate several hypotheses as to the mitigating effects operating experimentally. In this joint project, PPPL will lead the computational study, while TAE will provide physics input from their experimental and related theoretical studies. The larger fusion community will benefit from the published conclusions by advancing the understanding of these essential fast-particle physics in conditions which extend those studied in the mainline public–funded programs.