Using instrumentation on board the SAMPEX satellite at ~600 km we present new measurements of the composition of a population of >0.49 MeV/nucleon ions that are trapped near the geomagnetic equator. These ions gain access to the SAMPEX orbit as neutral particles via charge exchange collisions that continually occur within the higher altitude radiation belt and contribute to the decay of storm-time enhanced ring current. At low altitudes a second charge exchange collision produces a trapped ion belt near the magnetic equator. This belt is ephemeral, as it is necessarily observed on drift paths that reach deep into the atmosphere near the South Atlantic Anomaly. We find the relative abundances of H:He:C:O:Ne-Fe are 7000:7.5:0.14:1.0:0.03. The low altitude particles are underabundant in Z>8 ions compared to the radiation belt, possibly because the radiation belt Z>8 ions may not be stably trapped once they charge exchange to higher rigidities. We cannot rule out the possible contribution of trapped anomalous cosmic rays to the heavy ions observed above 0.49 MeV/nucleon in this low altitude population. ¿ 1998 American Geophysical Union