This paper is concerned with the formation of the acceleration region for electrons which produce the visible auroral arc (of a width less than the gyrodiameter of the plasma sheet protons) and with the formation of the inverted V precipitation region (of a width much greater than the proton gyrodiameter). The former is embedded in the latter, and both are associated with field-aligned current sheets carried by plasma sheet electrons. It is shown that an electron current sheet driven from the plasma sheet into the ionosphere leads to the formation of a two-dimensional potential double layer. For a current sheet of a thickness less than the proton gyrodiameter (corresponding to the visible auroral arc) we obtain solutions in which the field-aligned potential drop is distributed over a length much greater than the Debye length. For a current sheet of a thickness much greater than the proton gyrodiameter (corresponding to the inverted V structure) we obtain solutions in which the potential drop is confined to a distance on the order of the Debye length. The electric field in our two-dimensional double-layer model is the zeroth-order field inherent to the current sheet configuration, in contrast to those models in which the electric field is attributed to the first-order field due to current instabilities or turbulences. The maximum potential in our two-dimensional double-layer models is on the order of the thermal energy of plasma sheet protons, which ranges from 1 to 10 keV.