A comprehensive numerical study of ion acoustic double layers has been performed for both periodic and nonperiodic systems by means of one-dimensional particle simulations. For a nonperiodic system, an external battery and a resistance are used to model the magnetospheric convection potential and the ionospheric Pedersen resistance. It is found that the number of double layers and the associated potential buildup across the system increase with the system length. The potential jump ΔϕD across a single double layer is approximately eΔϕD/Te≈1 and the distance between two consecutive double layers is typically 1000 Debye length, where e and Te are the electronic charge and temperature. There is little interaction among double layers, and each double layer behaves almost independently of the others. The maximum increase of plasma energy through the enhanced resistance associated with double layer formation is found to be about 15% of the initial plasma energy for the parameters used in the simulations. The resistivity takes its maximum value at the instance when the double layers are just formed and then drops to almost zero afterwards, indicating the presence of a superconducting phase due to the formation of a quasistable Bernstein-Green-Kruskal type equilibrium. The equilibrium is, however, unstable with respect to the emission of ion acoustic solitons, and the double layers eventually decay as the solitons carry the energy away from the double layers propagating through a plasma toward the downstream direction.