The separation of the nightside auroral oval into two distinct regions, sometimes referred to as a double oval, is often observed during substorm recovery in global images from the Ultraviolet Imager (UVI) experiment. The two regions of auroral emission are both extended for a few hours of magnetic local time and are separated from one another by a few degrees in magnetic latitude. High-resolution, low-altitude data from the FAST spacecraft reveal that the two regions (1) represent distinct types of electron precipitation, (2) contain distinct types of ion distributions, and (3) are accompanied by a regular and repeatable field-aligned current pattern. A region of corotating plasma is often observed in conjunction with the equatorward region. The low-altitude particle measurements indicate that the equatorward emission is caused by the diffusion into the loss cone of ~2 keV electrons from the plasma sheet, while the poleward emission is caused by the electrostatic acceleration of electrons at much lower altitudes. The two regions represent electron energy fluxes of roughly the same magnitude (although the poleward flux is larger), but the poleward flux carries a substantial field-aligned current, while the equatorward flux does not. This low-altitude current pattern, interpreted in terms of ionospheric stress applied by convective flow in the tail, indicates that the equatorward emission is associated with very weak and uniform high-altitude flow, while the poleward emission is at the footpoint of strongly sheared dusk ward flow. ¿ 2001 American Geophysical Union