  Abundance enhancements, during acceleration and transport in both gradual and
impulsive solar energetic particle (SEP) events, vary approximately as power
laws in the mass-to-charge ratio [A/Q] of the ions. Since the Q-values depend
upon the electron temperature of the source plasma, this has allowed a
determination of this temperature from the pattern of element-abundance
enhancements and a verification of the expected inverse-time dependence of the
power of A/Q for diffusive transport of ions from the SEP events, with
scattering mean free paths found to be between 0.2 and 1 AU. SEP events derived
from plasma of different temperatures map into different regions in typical
cross-plots of abundances, spreading the distributions. In comparisons of SEP
events with temperatures above 2 MK, impulsive events show much broader
non-thermal variation of abundances than do gradual events. The extensive shock
waves accelerating ions in gradual events may average over much of an active
region where numerous but smaller magnetic reconnections, "nanojets", produce
suprathermal seed ions, thus averaging over varying abundances, while an
impulsive SEP event only samples one local region of abundance variations.
Evidence for a reference He/O abundance ratio of 91, rather than 57, is also
found for the hotter plasma. However, while this is similar to the solar-wind
abundance of He/O, the solar-wind abundances otherwise provide an unacceptably
poor reference for the SEP abundance enhancements, generating extremely large
errors.
