Recurrent energetic particle events associated with forward/reverse shock pairs near 4 AU in 1978

The elemental composition at energies near 1 MeV/nucleon has been studied for three recurrent energetic particle events during the period August-October, 1978, with the low-energy-charged-particle instruments on Voyager 1/2 near 4 AU. These events are associated with forward/reverse shock pairs in the solar wind as identified by the MIT plasma experiments on Voyager. In all three events, the flux increases associated with the reverse shocks showed enhancements in the He/H and CNO/H ratios compared to typical solar flare composition. The average C/O ratio for the three events was 0.68 which is larger than for normal solar flares but somewhat smaller than the average value found for corotating events at 1 AU during the previous solar minimum (1974-1976).