A magnetosphere‐thermosphere‐ionosphere electrodynamics general circulation model

Abstract

Abstract. A new simulation model of the thermosphere, the ionosphere, and the magnetosphere is presented. This model, which we call the magnetospherethermosphere-ionosphere electrodynamics general circulation model (MTIE-GCM), calculates the three-dimensional structure of the thermosphere and the ionosphere, the two-dimensional magnetospheric plasma convection in the equatorial plane of the magnetosphere, and the couplings among the thermosphere, the ionosphere, and the •nagnetosphere. The electrodynamic couplings induced by the auroral precipitation, the region 2 field-aligned currents, and the neutral winds are selfconsistently computed. The major drawback of the model is the use of a dipole magnetic field in the magnetosphere such that we do not expect to reproduce observations exactly but rather to predict only correct orders of magnitude. The MTIE-GCM is run for solar maximum conditions and moderate magnetic activity in a sample case, where the electric potential is imposed in the polar cap but calculated everywhere else, to study the electrodynamic couplings occurring at high latitudes. The neutral winds increase the north-south component and decrease the east-west component of the ionospheric electric field, corresponding to an enhancement of the shielding effect by 10%. The region 2 field-aligned currents and the distribution of the magnetospheric pressure present smaller modifications, suggesting that the magnetosphere acts partly as a current generator. However, the results could possibly be different if the polar cap electric potential were allowed to change due to the neutral winds.

Ionospheric control of the magnetosphere: conductance

“…the codes lack the ability to model high energy particles) and they most likely underestimate the heating which occurs during the reconnection process in the tail. The study presented by Ridley et al (2003) shows changes in the pressure distribution in the inner magnetosphere due to the thermosphere neutral winds, which were similar to those reported by Peymirat et al (1998) and Peymirat et al (2002), who use a more realistic model of the inner magnetospheric particles. Because the pressure changes were so similar, it is expected that the results found here are resprentative of the true magnetosphere.…”

Thermospheric Density and Wind Determination from Satellite Dynamics

“…These models include so-called Thermosphere Global Circulation Models (TGCMs) and localised, high resolution models [e.g., Crowley, 1991;Peymirat et al, 1998;. Recent versions are usually part of larger coupled thermosphere-ionosphere-magnetosphere models.…”

Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

“…Further re®nement was achieved by the additional incorporation of the plasmasphere, as by Namgaladze et al (1988). Because large-scale electrodynamics play an important role in the neutral and plasma dynamics of the upper atmosphere and in its interplay with the plasmasphere and magnetosphere, further development of the models led to the construction of thermosphere/ionosphere electrodynamics general circulation models (TIEGCMs) as, e.g., by Namgaladze et al (1991), Richmond et al (1992) and more recently by Peymirat et al (1998).…”