Pathfinder Reforged: A Design Study for Proton--Boron-11 Lattice Confinement Fusion Experiments with Rigorous Energy-Balance Diagnostics

The Pathfinder Reforged design study is conservative in its promises and ambitious in its diagnostics. [3, 18, 19] It does not claim that p–11B LCF will reach reactor-level performance or imminently power electric propulsion systems; recent analyses and NASA statements emphasize that current LCF reaction rates and understanding are far from enabling practical engines or power plants. [3, 19, 33, 39] Instead, the contribution of this work is to define an experiment that can decisively clarify whether a metal lattice environment provides significant, experimentally observable enhancement to p–11B fusion rates at accessible driver energies. [6, 9, 11] If such enhancement is verified and can be scaled, the most realistic terrestrial applications are not near-term grid baseload, but rather compact neutron and gamma sources for hybrid fusion–fission systems, decentralized radioisotope production for medical imaging and cancer therapy, and specialized industrial or remote power where small, robust units are more valuable than very large central plants. [33,34,37,38,40,42,43] If, instead, the experiment finds no measurable enhancement beyond updated nuclear data and modest screening, that null result still performs an important service by closing off a large design space of implausible solid-state aneutronic reactors and by refocusing fusion research on approaches better aligned with established physics. [3, 18, 19, 35] By combining enriched 11B targets, ultrafast lasers, and modern nuclear diagnostics and energy-balance tools, the experiment can deliver either positive evidence for such enhancement or strong constraints that limit how much enhancement is possible. [1, 2, 4, 13] This information is valuable regardless of the outcome: if large enhancements are ruled out, LCF-based p–11B concepts can be deprioritized; if modest or large enhancements are observed, new directions for aneutronic fusion research open up. [3, 18, 19]