Revisiting Heliosheath Flows from Voyager Observations

Since Voyager 2 crossed the termination shock in 2007 and the heliopause in 2018, the radial flow speed in the heliosheath () has remained uncertain due to persistent discrepancies between measurements from the Plasma Science (PLS) instrument and values inferred from energetic particle observations using the Compton–Getting (CG) effect. These differences are critical because they directly impact our understanding of heliosheath structure and dynamics and play a central role in validating global magnetohydrodynamic (MHD) models. In this work, we revisit the estimation of heliosheath flow speeds from Low-Energy Charged Particle (LECP) data by expanding the legacy CG-based method to account for anisotropic particle distributions in the plasma frame and by combining measurements from multiple energy channels. These refinements provide a more physically realistic interpretation of particle anisotropies and CG-derived flow speeds and offer a pathway toward reconciling plasma and particle measurements of heliosheath flows.