Nonlinear power enhancement factor for spin‑polarized D–T fuel

Ascertain the nonlinear power enhancement factor N for deuterium–tritium spin‑polarized fuel corresponding to specified spin‑polarization cross‑section multipliers A_J (e.g., A_J = 1.25), by quantifying alpha‑heating feedback and plasma‑parameter changes in D–T conditions. Establishing N for D–T will enable accurate specification of the effective polarization multiplier N A_J in predictive models and comparisons with D–He3 experimental results.

Background

The analysis uses a factor N to capture reported nonlinear increases in fusion power beyond the cross‑section enhancement A_J when fuel is spin‑polarized, reflecting alpha‑heating effects. Upcoming spin‑polarization experiments on D–He3 will provide relevant data, but translating those results to D–T requires determining the appropriate N under D–T plasma conditions.

Accurate knowledge of N for D–T is critical because the product N A_J directly enters the power‑density and gain calculations; uncertainty in N propagates to predictions of tritium burn efficiency, startup inventory, and operational trade‑offs in spin‑polarized, low‑tritium‑fraction regimes.