In a groundbreaking development for fusion energy, researchers at the National Ignition Facility (NIF) have observed novel physical phenomena in inertial confinement fusion (ICF) burning plasma. This discovery, reported in January 2025, marks a pivotal step in understanding the extreme conditions similar to those of the early universe.
The study led by Prof. Jie Zhang from the Institute of Physics of the Chinese Academy of Sciences and Shanghai Jiao Tong University revealed significant deviations in neutron spectrum data from hydrodynamic predictions, indicating the presence of supra-thermal deuterium-tritium (DT) ions. These findings challenge established models based on Maxwellian distributions by highlighting previously overlooked kinetic effects and non-equilibrium mechanisms.
The research team developed a large-angle collision model that incorporates the screened potentials of background ions and the relative motion of ions during binary collisions. This approach effectively captures the complex ion kinetics, leading to the creation of the hybrid-particle-in-cell LAPINS code, which enables high-precision simulations of ICF burning plasmas.
Key advancements from this research include:
A 10 picosecond improvement in ignition timing.
Detection of supra-thermal deuterium ions below an energy threshold of approximately 34 keV.
Nearly double the expected peak densities of alpha particles.
A 24% increase in alpha particle densities at the hotspot center.
The alignment of neutron spectral moment analyses from NIF with the kinetic simulations reinforces the validity of these findings, showcasing significant discrepancies that grow with increasing yield. This research not only enhances the interpretation of experimental results but also opens new avenues for refining ignition designs and exploring nuclear burning plasmas.
These insights into the complex physics of nuclear burning plasmas could potentially lead to advancements in fusion energy technology, paving the way for sustainable energy sources that mimic the processes of the early universe.