Year: 2024
Type: article
Abstract: At a low activity comet the plasma is distributed in an asymmetric way. The hybrid simulation code Amitis is used to look at the spatial evolution of ion velocity distribution functions (VDFs), from the upstream solar wind (SW) to within the comet magnetosphere where the SW is heavily mass‐loaded by the cometary plasma. We find that the spatial structures of the ions and fields form a highly asymmetric induced magnetosphere. The VDFs of SW and cometary ions vary drastically for different locations in the comet magnetosphere. The shape of the VDFs differ for different species. The SW protons show high anisotropies that occasionally resemble partial rings, in particular at small cometocentric distances. A second, decoupled, proton population is also found. Solar wind alpha particles show similar anisotropies, although less pronounced and at different spatial scales. The VDFs of cometary ions are mostly determined by the structure of the electric field. We perform supplementary dynamic particle backtracing to understand the flow patterns of SW ions that lead to these anisotropic distributions. This tracing is needed to understand the origin of cometary ions in a given part of the comet magnetosphere. The particle tracing also aids in interpreting observed VDFs and relating them to spatial features in the electric and magnetic fields of the comet environment.
DOI: 10.1029/2024ja032757
Institutions: Swedish Institute of Space Physics, Umeå University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,880
Awards: Advanced atomistic modeling of radiation damage in high-temperature superconductors for nuclear fusion application, Comparative Magnetospheres: Mars and Comets, G3151249029, Magnetosphere-Interior Coupling at Mercury During Extreme Solar Events, War and Water - Coping with Conflict-induced Water Shortage, NAISS
OpenAlex ID: W4402591421