Comparing Solar Flares With and Without Proportional Acceleration of >~20 MeV Protons and Electrons Above Various Energies

A large fraction (tens of percent) of the energy released in solar flares goes into accelerated ions and electrons, and studies indicate that these two populations have comparable energy content. RHESSI observations have shown a striking close linear correlation between the 2.223 MeV neutron-capture gamma-ray line and electron bremsstrahlung emission >300 keV, indicating that the flare acceleration of >~20 MeV protons and >300 keV electrons is roughly proportional over >3 orders of magnitude in fluence. We investigate how this correlation between ion and electron acceleration weakens when comparing against electrons above various lower-energy thresholds, with a number of flares that appear to have a significant relative excess of low-energy bremsstrahlung emission compared to other flares. We take a close look at these particular flares and discuss possible explanations for the observed behavior.