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arXiv · 2604.06769

Monte Carlo Simulations of Suprathermal Enhancement in Advanced Nuclear Fusion Fuels

Marcus Borscz·Thomas A. Mehlhorn·Patrick A. Burr·Igor Morozov·Sergey Pikuz
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Abstract

Suprathermal fusion reactions, initiated by energetic particles slowing down and scattering in dense plasmas, can modify the burn dynamics at inertial confinement fusion (ICF) regimes. A 0D time-dependent Monte-Carlo code has been developed to assess the suprathermal energy gain from fast fusions in DT, deuterium, $^{11}$BH$_3$ and $^{11}$BHDT fuels. It incorporates modified Li-Petrasso stopping powers, thermal broadening of cross-sections, anisotropic nuclear elastic and neutron elastic scattering, and a physical model for the p$^{11}$B alpha-particle spectra. Results show that earlier predictions of suprathermal criticality in pure deuterium are overestimated by more than an order of magnitude; no realistic density-temperature regime supports a self-sustaining chain reaction. Only DT demonstrates a critical regime provided there is no neutron leakage. Fast protons in $^{11}$BH$_3$ have an optimum energy of 4 MeV for maximising suprathermal enhancement. In this case the additional energy from fast fusions is unlikely to exceed 40% of the initial proton beam energy. The possibility of an alpha-particle-driven "avalanche" mechanism is ruled out since the ionic stopping is dominated by collisions involving small energy transfer. Suprathermal multiplication processes are dominated by neutron-driven ion up-scattering and likely play a limited role in purely aneutronic fuels.

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Marcus Borscz, Thomas A. Mehlhorn, Patrick A. Burr, Igor Morozov, Sergey Pikuz. 2026-04-08. Monte Carlo Simulations of Suprathermal Enhancement in Advanced Nuclear Fusion Fuels. https://arxiv.org/abs/2604.06769

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