Interactions of Ionospheric and Magnetospheric Plasmas: Numerical Simulations with One Model
Historically, understanding the basic physics of the terrestrial ionosphere and its interactions with the transient solar wind plasma benefited greatly from first-principles computer models describing the chemistry and electrodynamics of ionospheric plasmas, while interactions with the magnetospheric populations was prescribed as external “inputs”, or “driving”. Similarly, first-principles simulations of the terrestrial magnetosphere, whether regional kinetic or global magnetohydrodynamic, treated the ionosphere in a highly simplified manner, usually in the form of a boundary condition applied on a two-dimensional shell placed at ionospheric altitudes. This talk will describe development of and results from a numerical model that goes beyond some of these simplifications. The model is based on the SAMI3 NRL three-dimensional ionosphere code and the RCM (Rice Convection Model) inner magnetosphere code. The model evolves in time two sets of equations, one for partially ionized ionospheric collisional plasma, the other for fully ionized collisionless magnetospheric plasmas. The equations are coupled via electrostatic potential that enters the transport terms in both sets of equations and is solved for as part of the RCM equations. The talk will describe numerical simulations of this coupled ionosphere-magnetosphere system for several events when coronal mass ejections produced geomagnetic storms, with available ground-based, low-altitude, and magnetospheric observations. Results of these simulations demonstrate how storm-time magnetospheric electric fields control structuring of the ionospheric layers (particularly the F-layer) at different latitudes on various time scales, what kind of feedback the ionosphere exerts on the magnetosphere, and to what extent these self-consistent solutions are supported by observations.