46th International Workshop on High Energy Density Physics with Intense Ion and Laser Beams

Ion stopping in dense plasmas is fundamental for understanding the plasma transport properties with direct implications for inertial confinement fusion, high-energy-density physics and laboratory astrophysics. This process remains poorly understood when the ion-plasma coupling parameter exceeds unity - a nonlinear regime where non-perturbative screening play an important role. We report a controlled experimental study of stopping power in this nonlinear regime using laser-accelerated quasi-monoenergetic highly charged carbon ions near Bragg peak and a well-characterized dense plasma (Te = 17 eV, ne = 4×10²⁰ cm⁻³) target. Through simultaneously tracking the charge-state distributions and energies of ions traversing plasma, the prevailing stopping models are tested eliminating the uncertainties associated with the effective charge states predictions. All the perturbative models, including BPS, Li–Petrasso, Bethe, T-matrix, and Vlasov formulas, overestimate the measured energy loss. In contrast, classical molecular dynamics simulations, which can self-consistently capture the nonlinear screening effects, closely reproduce the data when augmented by a quantum-diffraction correction that suppresses the small-angle scattering. Our results demonstrate the failure of linear-response treatments under non-linear ion-plasma coupling regime and validate a hybrid framework of classical MD theory with quantum correction. This work established a platform to probe the complex collisional dynamics in plasma, offering insight into the accuracy of energy and particle flow models.