Night-side chorus waves are often observed during plasma sheet injections, typically confined around the equator and thus potentially responsible for precipitation of $\lesssim 100 keV$ electrons. However, recent low-altitude observations have revealed the critical role of chorus waves in scattering relativistic electrons on the night-side. This study presents a night-side relativistic electron precipitation event induced by chorus waves at the strong diffusion regime, as observed by the ELFIN CubeSats. Through event-based modeling of wave propagation under ducted or unducted regimes, we show that a density duct is essential for guiding chorus waves to high latitudes with minimal damping, thus enabling the strong night-side relativistic electron precipitation. These findings underline both the existence and the important role of density ducts in facilitating night-side relativistic electron precipitation.

Previous statistical studies have described the distributions and properties of whistler-mode waves in Jupiter’s magnetosphere, but explaining these wave distributions requires modeling wave propagation from their generation near the magnetic equator. In this letter, we conduct ray tracing of whistler-mode waves based on realistic Jovian magnetic field and density models. The ray tracing results generally agree with the statistical wave distributions based on Juno measurements. The modeled ray paths show that high-frequency waves generated near the equator are confined within 20° magnetic latitude due to Landau damping, low-frequency waves can propagate to higher latitudes and lower M-shells, with changing wave normal angles, and a portion of low-frequency waves could propagate to high M shells at high latitudes. Our modelling results provide a theoretical interpretation of whistler-mode wave distributions and properties, providing essential insights for future radiation belt models at Jupiter.