Heliospheric Termination Shock Mediation by Anomalous Cosmic Rays: Insights from Recent Voyager Data

Abstract

The two Voyager spacecraft provide valuable information about the energetic particle population near the termination shock (TS), such as the anomalous cosmic ray (ACR) spectra, the intensity gradients, and the radial diffusion coefficients obtained from anisotropy measurements. While the spectra and gradients have been modeled successfully using the test-particle approach, the shock modification by the ACR pressure gradient has not yet been addressed in the full context of the available data. Here we present the results of a self-consistent axisymmetric model of the solar wind modified by both charge exchange and ACR pressure gradients. Our results indicate that during solar minima anomalous cosmic rays with energies above 100 keV are not likely to have a significant impact on the properties of the termination shock.