A STUDY OF THE COMPOSITION AND ENERGY-SPECTRA OF ANOMALOUS COSMIC-RAYS USING THE GEOMAGNETIC-FIELD

We use instrumentation on SAMPEX and the Earth's field as a magnetic r igidity filter in a ''double spectrometer'' approach to measure the co mposition and energy spectra of anomalous cosmic rays (ACRs) with Z gr eater than or equal to 6. A ''pure'' sample of anomalous cosmic ray C, N, O, and Ne is obtained, with no significant evidence for other spec ies. The bulk of ACRs are now known to be singly-charged, and the geom agnetic filter allows their energy spectra to be measured to higher en ergies than before. The anomalous oxygen spectrum is found to extend t o at least similar to 100 MeV/nuc, which has implications for models o f the acceleration of these ions.