Electron Physics in 3D Two-Fluid Ten-Moment Modeling of Ganymede's Magnetosphere

TL;DR

This study uses a 3D two-fluid ten-moment model to analyze electron physics in Ganymede's magnetosphere, revealing insights into magnetic topology, reconnection processes, and emission morphology consistent with observations.

Contribution

It introduces a detailed 3D two-fluid ten-moment simulation capturing non-ideal electron physics, advancing understanding of Ganymede's magnetospheric dynamics.

Findings

Magnetic field topology agrees with Galileo measurements.

Pressure anisotropy influences magnetic reconnection.

Surface emission patterns correlate with electron and ion pressure variability.

Abstract

We studied the role of electron physics in 3D two-fluid 10-moment simulation of the Ganymede's magnetosphere. The model captures non-ideal physics like the Hall effect, the electron inertia, and anisotropic, non-gyrotropic pressure effects. A series of analyses were carried out: 1) The resulting magnetic field topology and electron and ion convection patterns were investigated. The magnetic fields were shown to agree reasonably well with in-situ measurements by the Galileo satellite. 2) The physics of collisionless magnetic reconnection were carefully examined in terms of the current sheet formation and decomposition of generalized Ohm's law. The importance of pressure anisotropy and non-gyrotropy in supporting the reconnection electric field is confirmed. 3) We compared surface "brightness" morphology, represented by surface electron and ion pressure contours, with oxygen emission observed by the Hubble Space Telescope (HST). The correlation between the observed emission morphology and spatial variability in electron/ion pressure was demonstrated. Potential extension to multi-ion species in the context of Ganymede and other magnetospheric systems is also discussed.