An Enhanced "Flux-Corrected Transport"-Based Plasmasphere Refilling Model

TL;DR

This paper extends a plasmasphere refilling model by including self-consistent electron temperature evolution, enabling more accurate simulation of ion transport and plasma recovery processes after geomagnetic storms.

Contribution

The model now incorporates spatially and temporally varying electron temperature, improving physical realism in simulating plasmasphere refilling dynamics.

Findings

Model reproduces dominant H+ behavior and early O+ contributions.

Enhanced temperature modeling clarifies ion transport mechanisms.

Results are robust across different L-shells and initial conditions.

Abstract

A previously developed multi-ion, two-stream Flux-Corrected Transport (FCT) hydrodynamic model for plasmasphere refilling has been extended to incorporate self-consistent electron temperature evolution. The past assumption of a constant temperature along the modeled flux tube has been replaced by solving the electron energy equation, permitting spatially and temporally varying temperature. This improvement provides a more physically complete representation of the pressure and ambipolar electric-field gradients that influence ion transport. The extended model allows us to investigate two-stage refilling behavior established by prior observations and simulations. The model continues to reproduce the expected dominance of H+, enhanced early-time O+ contributions, and the coupling between H+ and He+ through the ambipolar electric field during the transition between stages. Sensitivity experiments with modified initial ion concentrations, including cases representing seasonal effects, highlight the distinct roles of each ion species in shaping the refilling trajectory. Comparisons across L-shells 3 and 4 further confirm the robustness of the model framework for future extension to three-dimensional geometries. Overall, by incorporating more realistic temperature variations, this enhanced model strengthens the physical understanding for interpreting complex multi-ion transport processes during plasmasphere recovery following geomagnetic storms.