Nonequilibrium effects in high-gain inertial confinement fusion

SX Hu and NR Shaffer and B Arnold and KA Nichols and VV Karasiev and S Zhang and VN Goncharov, PHYSICAL REVIEW E, 111, L053202 (2025).

DOI: 10.1103/PhysRevE.111.L053202

Recent experimental demonstrations of ignition and target gain in inertial confinement fusion (ICF) have stimulated interest in exploring the fundamental physics of violent deuterium-tritium (DT) burn in high- gain ICF targets. A significant DT-burn fraction is a necessary condition for high energy gain and large neutron yields (>100 MJ). Using classical molecular-dynamics (MD) simulations and a hybrid fluid-kinetic model, we examine how a large fraction of low-energy alpha particles can kick D and T ions out of equilibrium in high-gain ICF targets. The MD results suggest that (1) temperatures of T-D and T-T can differ by as much as '20% of their mean temperature and (2) the deviation of the DT energy distribution from the Maxwell-Boltzmann function can exceed '30%. Some of these MD observations, such as the preferential heating of D ions by low-energy alpha particles and the temperature separation, can be explained by a proposed hybrid fluid-kinetic model. The implication of such nonequilibrium effects on the DT reactivity is also discussed.

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