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arXiv · 2506.02273

Particle-in-Cell Simulations of Burning ICF Capsule Implosions

Johannes J. van de Wetering·Justin R. Angus·W. Farmer·V. Geyko·D. Ghosh·D. Grote·C. Weber·G. Zimmerman
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Abstract

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.

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Johannes J. van de Wetering, Justin R. Angus, W. Farmer, V. Geyko, D. Ghosh, D. Grote, C. Weber, G. Zimmerman. 2025-06-02. Particle-in-Cell Simulations of Burning ICF Capsule Implosions. https://arxiv.org/abs/2506.02273

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