2025/06/02 by Johannes van de Wetering, van de Wetering, Johannes J., J. R. Angus +13
Engineering · #Combustion and Detonation Processes #Computational Physics (physics.comp-ph) #Energetic Materials and Combustion #FOS: Physical sciences #Particle Dynamics in Fluid Flows #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.2506.02273
openalex publication_date 2025/06/02 · openalex created_date 2025/10/14 · openalex updated_date 2026/07/28
Anomalies observed in the neutron spectral shift of high-yield shots at the National Ignition Facility (NIF) suggest the presence of suprathermal ions, implying that kinetic effects play a significant role in burning inertial confinement fusion (ICF) plasmas. Furthermore, recent measurements of reaction-in-flight (RIF) neutrons offer a direct probe of the stopping power in the burning fuel region of high energy alpha particles and up-scattered fuel ions. We have developed the particle-in-cell code PICNIC, an exactly energy-conserving particle-in-cell Monte-Carlo collision (PIC-MCC) code to simulate the burn stage in ICF. We present results from 1D spherical simulations of NIF shot N210808. We find that the suprathermal ions generated by large-angle Rutherford and nuclear elastic scattering (NES) with fusion alphas produce an alpha knock-on neutron (AKN) signal consistent with experiments. We also find that the inclusion of large-angle scattering physics does not explain the anomalously large spectral shift observed in experiment.