3D Time-Domain Multifluid Nonlinear Simulations of Alfven Wave Based Magnetosphere-Ionosphere Coupling
Dr. Aaron West
Abstract: Alfven waves transport energy throughout planetary magnetospheres, coupling distant plasma populations through local wave-particle and wave-wave transfers. Earth's ionospheric conductance reflects low frequency Alfven waves, leading to low altitude wave interference. Pedersen and Hall currents in the ionosphere damp away incident narrow wave features from atmospheric propagation, preventing ground magnetometer detection. Satellite orbits do not often probe these lower altitudes with broad spatio-temporal coverage. Rocket missions can sample instantaneous plasma environments, but cannot distinguish temporal from spatial features.
We simulate this difficult to reach plasma environment through a recently constructed nonlinear multifluid plasma model using high resolution energy conserving finite volume methods. We examine plasma wave behavior in the simulated domain under a variety of common magnetosphere conditions by modifying the ionospheric conductances, magnetospheric density profile, and background magnetic field. We find that ionospheric parameters modulate Alfven wave perpendicular coherence length at low altitudes. This supports the growth of inertial Alfven waves and subsequent energy damping through electron acceleration. Multifluid analysis of intra-wave electron and ion current flows during inertial Alfven wave growth reveals plasma species decoupling over short time scales. This analysis is performed in Earth and Jupiter plasma environments.
Bio: Aaron West is a postdoctoral researcher at the University of Minnesota working on non-linear simulations of Alfven wave-particle acceleration in both the Terrestrial and Jovian magnetospheres. He defended his PhD in 2025 titled "Nonlinear multi-fluid modeling of kinetic Alfven waves in planetary magnetospheres" and is now pursuing future employment at the University of Alberta, Canada. He specializes in multifluid plasma simulations, physics of kinetic plasma, chaos theory, and plasma turbulence.