Shock acceleration of nuclei and electrons in the Heliosphere beyond 24 AU

Radially propagating shocks of solar flare origin are analyzed using plasma and charged particle measurments on Pioneer 10 to show that protons and helium nuclei are continuously accelerated to energies of up to roughly 70 MeV per nucleon. The discovery that electrons are simultaneously accelerated to relativistic energies places new constraints on models for acceleration by these quasi-perpendicular shocks in the outer heliosphere