Relation between the solar wind dynamic pressure at Voyager 2 and the energetic particle events at Voyager 1

Abstract

Starting in 2001, Voyager 1 observed three events characterized by enhanced fluxes of energetic particles. These events suggest that Voyager 1 made a close approach to, or a crossing of, the termination shock. Although the plasma experiment on Voyager 1 is not providing useful data, plasma data from Voyager 2 may shed light on the plasma conditions at Voyager 1. Before the first particle event, Voyagers 1 and 2 see similar particle signatures. Voyager 2 pressure and energetic particle flux profiles have similar structure. The merged interaction regions (MIRs) observed at Voyager 2 have counterparts in the Voyager 1 data. We propagate solar wind data from Voyager 2 to Voyager 1 and show that at the predicted MIR arrival times, there is always a response in the Voyager 1 particle data. These effects vary, from an increase in particle flux to a rapid turnoff of the particle event. We discuss the observed energetic particle effects and how the MIRs produce them.