Observations from the ion detectors on Defense Meteorological Satellite Program satellites F6 and F7 have revealed an interesting phenomenon, namely the existence of isolated and latitudinally narrow regions of ion precipitation up to ~1 kEV well within the plasmasphere. Using the almost continuous coverage afforded by the 101-min polar orbits of these satellites, we are able to document in detail the process whereby such isolated precipitation patterns are established. Prolonged intense substorm activity is observed to introduce plasma of sub-keV energy from the earthward edge of the plasma sheet to deep within the plasmasphere (at least L=2.4). The plasma introduction occurs over a confined magnetic local time (MLT) range extending from somewhere postmidnight to about 0830 MLT. Because of their much more rapid pitch-angle scattering into the loss cone, the energetic electrons are lost within one or two hours, whereas the ions can persist for at least a day. After being injected into low L values, the ions begin to corotate, thereby forming latitudinally narrow and well-isolated structures of ion precipitation far below the instantaneous auroral oval. The total number of ions injected over a several-hour span can be very roughly estimated to be ~1025. Because of certain similarities of the injection process to observations by Lennartsson and Sharp (1982) and to the magnetic storm time observations of Shelley et al. (1972) and Strangeway and Johnson (1984), it is likely that the low-latitude precipitating ions are O+.