Abstract
This paper discusses a numerical modulation model to describe anomalous cosmic ray acceleration and transport in the heliosheath, the portion of the heliosphere between the termination shock and the heliopause. The model is based on the well known Parker transport equation and includes, in addition to diffusive shock acceleration at the solar wind termination shock, momentum diffusion (Fermi II, stochastic acceleration) and adiabatic heating occurring in the heliosheath together with both a latitude dependent compression ratio and injection efficiency as inferred from hydrodynamic heliospheric models. The model is applied to the study of anomalous cosmic ray oxygen, with the resulting intensities compared to recent Voyager 1 spacecraft observations in the heliosheath. Comparison shows that the model is able to very satisfactorily reproduce these observations, which includes a modulated spectral form at the termination shock and subsequent unfolding into the heliosheath. It is concluded that a combination of momentum diffusion and adiabatic heating, under certain realistic assumption of the solar wind speed in the heliosheath, form a viable re-acceleration mechanism, or continuous acceleration process, to explain the very contentious anomalous cosmic ray observations in the heliosheath.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
