Measurements of low energy electrons and ions during long-lived solar particle events

Following a solar flare in April 1979, a stream of ions and electrons appeared in interplanetary space for about 8 days. The ions follow a classic ESP pattern. Large fluxes of low energy (2–11 keV) electrons are also present throughout the event. Several distinct populations of these electrons can be identified in association with filaments of interplanetary magnetic field. The electron energy spectrum is remarkably well fit by a power law exponent -2.7 during most of the event.The pitch angle distribution of the low energy electrons are complex and undergo many changes. Weak pitch angle scattering and adiabatic effects play a role in shaping these distributions. The low energy electron fluxes increase following the strong interplanetary shock on 5 April 1979.An invited paper presented at STIP Workshop on Shock Waves in the Solar Corona and Interplanetary Space, 15–19 June, 1980, Smolenice, Czechoslovakia.Physics Department and Space Sciences Laboratory.Space Sciences Laboratory.