On the Energy Balance of the D–T Fusion Reaction in Tokamak Plasmas

This preprint presents a focused analysis of the energy balance of the D–T fusion reaction in tokamak plasmas. While the released energy per reaction (17.6 MeV) is well established and reliably quantified via neutron diagnostics, the global energy balance over the reaction duration—including the energy required to sustain plasma conditions—remains non-positive in present-day experiments. To address this discrepancy, the note introduces a minimal phenomenological parameter, the coherence participation factor f∼10' -3 interpreted as the fraction of the internal reaction energy that becomes observable within standard kinetic and thermal diagnostic frames. The factor follows from geometric and phase-dynamic considerations and does not modify reaction cross sections, branching ratios, or conservation laws. The proposed interpretation is consistent with experimental observations of Alfvénic and field activity driven by energetic particles in D–T and D–³He plasmas. It suggests that a portion of fusion energy may be redistributed into collective field and wave channels—such as Alfvénic, infrared, and electromagnetic-like regimes—that are not explicitly accounted for in conventional energy balance analyses. The work remains fully within the standard experimental and diagnostic framework and proposes the use of existing measurements to search for correlations between fusion output and phase-coherent magnetic activity beyond traditional diagnostic windows. This preprint is linked to a broader theoretical framework describing coherence and domain-scale energy redistribution:https://doi.org/10.5281/zenodo.18265856