How do Cosmic Rays enter and leave the Heliosphere?

Abstract

The surprisingly abrupt increase of GCRs at the heliopause (HP) seen by both Voyager spacecraft poses a challenge to conventional diffusion models and raises the question how do galactic and anomalous cosmic rays (GCRs and ACRs) enter or leave the heliosphere. In this speculative work we address the possibility that heliospheric currents sheets (HCSs) may provide channels of fast cosmic-ray transport and can act as cracks on the HP. By virtue of fast particle drifts along the HCS, cosmic rays find an easier access to and from the heliosphere at places where a HCS reaches the HP. Numerical simulations adopting a simple toy models is presented and and discussed. The possible dynamical role of GCRs and ACRs on the formation of the HP is briefly addressed. We suggest that the jump in the GCR intensity and the leakage of ACR through the HP might be responsible, in part, for the apparent imbalance between the total pressure inside and outside the HP. Furthermore, the leakage of ACRs might contribute to the flatter than expected size of the inner heliosheath between the termination shock (TS) and HP. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)