Global ten-moment multifluid simulations of planetary magnetospheres

Capturing magnetospheric physics at global scales in simulations requires careful consideration of both computational cost and physics fidelity. The need to capture physics at a variety of disparate scales with reasonable cost generally forces approaches into either enhanced magnetohydrodynamic models, or hybrid solvers which treat the ions as particles while maintaining fluid electrons. Both approaches struggle to capture all the relevant electron dynamics that occur at kinetic scales, particularly near the magnetopause and in the magnetotail where magnetic reconnection regularly occurs. The Gkeyll software's multifluid solver for the ten-moment equations is uniquely positioned to address many of the weaknesses of previous approaches by self-consistently capturing electron dynamics and agyrotropic effects through full evolution of the pressure tensor, in a unified fluid framework without requiring any direct solution of the kinetic equation. We present here improvements made to the fluid solver in Gkeyll including embedded surface geometries, a gradient-based heat flux closure taking into account anisotropic flows from field geometry, and resistivity of the planetary crust. Global planetary magnetosphere simulations are performed, demonstrating the fidelity of the ten-moment solver.