  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.
