The University of California at San Diego Auroral Particles Experiment on the ATS 6 satellite in synchronous orbit has detected a low-energy plasma population which is separate and distinct from both the ring current and the plasma sheet populations. The density and temperature of this low-energy population are highly variable, with temperatures in the range kT=1-30 eV and densities ranging from less than 1 cm-3 to more than 10 cm-3. The occurrence of a dense low-energy plasma is most likely in the afternoon and dusk local time sectors, whereas n$1 cm-3 is seen in the local night sector only during magnetically quiet periods. These observations suggest that this plasma is the outer zone of the plasma-sphere. During magnetically active periods this low-energy plasma is often observed flowing sunward. In the dusk sector, strong sunward plasma flow is often observed for 1-2 hours prior to the onset of a substorm-associated particle injection.