Measurements of the Ionic Charge States of Solar Energetic Particles at 15-70 MeV/nucleon

The mean charge states of abundant heavy ions with ~15 - 70 MeV/n in the two large solar energetic particle (SEP) events of 1992 October 30 and November 2 have been determined using measurements of invariant latitude of the geomagnetic cutoffs as a function of time, particle energy, and element from the Mass Spectrometer Telescope (MAST) on SAMPEX. The deduced charge state values are in good agreement with the mean values measured directly in previous SEP events at much lower energies of ~1 MeV/n, with inferred equilibrium source temperatures of typically 2 x 10^6 K, which provides additional evidence that SEPs in gradual-type events are accelerated coronal material.