Comment on “ENN's roadmap for proton-boron fusion based on spherical torus”

What is it about?

This comment discusses the feasibility of hot ion mode Ti/Te=4 for proton–boron fusion, which is critical for the roadmap proposed in Liu et al. [Phys. Plasmas 31, 062507 (2024)]. The hot ion mode Ti/Te=4 has been calculated to be far from accessible ( Ti/Te<1.5 for Ti=150 keV) under the most optimal conditions if fusion provides the heating [Xie, Introduction to Fusion Ignition Principles: Zeroth Order Factors of Fusion Energy Research (USTC Press, Hefei, 2023)], i.e., that all fusion power serves to heat the ions and that electrons acquire energy only through interactions with ions. We also discuss if hot ion mode of Ti/Te=4 could be achieved by an ideal heating method, which is much more efficient than fusion itself (near 20 times fusion power for Ti=150 keV) and only heats the ions, whether it makes sense economically.

Featured Image

Photo by Lavi Perchik on Unsplash

Photo by Lavi Perchik on Unsplash

Why is it important?

This comment article showed that the hot ion mode approach to achieve proton-boron has serious defect deeply rooted in achieving and sustaining it.The hot ion mode proposed to achieve proton-boron fusion demands a power much larger than fusion power to sustain even if the heating power is idealized. If the heating power is not idealized, such as NBI which is much less efficient, the power needed would be even larger. The calculation Q=30 was due to the omission of the electron ion thermal exchange P_ie and the power to sustain nonequilibrium distribution without reason.

Perspectives