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Researchers conducted the first experimental investigation of ion stopping power in dense plasma at strong ion-plasma coupling (coupling parameter exceeding unity). Using laser-accelerated carbon ions sent through a well-characterized dense plasma target, they observed a clear reduction in stopping power compared to predictions from standard linear models. The experimental results aligned with advanced hybrid molecular dynamics calculations that incorporate quantum corrections, demonstrating the importance of nonlinear screening and quantum effects in strongly coupled plasmas.
Why it matters
This work provides a crucial experimental benchmark for understanding energy transport in extreme conditions relevant to inertial confinement fusion and stellar physics. The findings will enable more accurate modeling of fusion ignition processes and stellar evolution, potentially improving predictions for fusion energy research and astrophysical phenomena.
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arXiv:2606.23109v2 Announce Type: replace
Abstract: Ion stopping in dense plasma is crucial for stellar evolution and fusion ignition. However, its behavior in the strong ion-plasma coupling regime beyond the linear limit has long remained elusive, due to formidable experimental challenges. Here we report the first experimental investigation of ion stopping at an unprecedented coupling parameter exceeding unity, achieved by sending laser-accelerated short-pulse and intense quasi-monoenergetic carbon ions ($sim$583 keV/u, C$^{5+}$) into a uniform, long-lived, well-characterized dense plasma target ($T_e$ $approx$ 17 eV, $n_e$ $approx$ 4$times$10$^{20}$ cm$^{-3}$). By simultaneously measuring ion energy loss and charge-state evolution, we eliminated key experimental ambiguities arising from charge-state determination. Our results clearly show a reduction in stopping power compared with predictions from standard linear dielectric response or binary collision models, and they agree well with the hybrid calculation of molecular dynamics with quantum corrections. The importance of nonlinear screening effects arising from many-body interactions and quantum effects due to the wave nature of electrons was demonstrated at strong coupling. This work establishes a definitive high-fidelity experimental benchmark for collisional dynamics in the strong-coupling regime. It offers critical insight for accurate modeling of energy transport in inertial confinement fusion and astrophysical plasmas.
Source: Observation of stopping power reduction at strong ion-plasma coupling