Inductive-Dynamic Simulation of Magnetosphere-Ionosphere Coupling in Dyside Cusps and Auroral Oval

Abstract:

We have developed a new numerical simulation model of the ionosphere/thermosphere by using an inductive-dynamic approach (including self-consistent solutions of Faraday’s law and retaining inertia terms in ion momentum equations), that is, based on magnetic field B and plasma velocity v (B, v paradigm), which is distinctive from the conventional modeling based on electric field E and current j. The model solves self-consistently time-dependent continuity, momentum, and energy equations for multiple species of ions and neutrals including photochemistry, and Maxwell’s equations. The governing equations solved in the model are a set of multifluid-collisional-Hall MHD equations which are one of unique features of our ionosphere/thermosphere model. With such an inductive-dynamic approach, not only sound wave mode but also all possible MHD wave modes are retained in the solutions of the governing equations so that the dynamic coupling between the magnetosphere and ionosphere and among different regions of the ionosphere can be self-consistently investigated.

In this presentation, we describe the algorithm of the simulation model and investigate dynamic coupling processes of magnetosphere-ionosphere in the dayside cusps and auroral oval through simulations. We show the propagation of disturbances from the magnetosphere along the magnetic field lines down to the ionosphere/thermosphere in Alfven speed, the mode conversion to fast mode MHD waves in the ionosphere and their propagation from the dayside cusps/auroral oval to the low latitude/equatorial ionosphere, thus providing a comprehensive and physically faithful explanation of the magnetosphere-ionosphere coupling as well coupling among different regions of the global ionosphere through MHD waves.