Motivated by our recent proposition on the possibility of using dielectric continuum models to interpret experimental measurements of solvation dynamics in room temperature ionic liquids [J. Phys. Chem. A110, 8623 (2006)], some detailed simulation studies are performed to test the validity of our proposition. From these simulation studies, it seems to be justified that an extended Debye–Hückel continuum model can be used to understand the solvation dynamics of ionic fluids. The theoretical underpinning of such an extended Debye–Hückel model is presented from the general dispersion relation in electrodynamics. The connection with the static extension from the dressed ion theory of electrolyte solutions is also discussed. Such a connection between the Debye–Hückel theory and the dispersion relation may be exploited to enhance our understanding of the electric double layer problem not only for the static case but also for dynamic situations.