March 29, 2013, 12:00 pm - 1:00 pm

March 29, 12:00 pm - 1:00 pm

What limits Magnetospheric models?

Ray Walker, Program Director For Magnetospheric Physics at NSF

Over the past thirty years global magnetohydrodynamic (MHD) simulations of the solar wind, magnetosphere and ionosphere system have become the workhorses of magnetospheric modeling. They have successfully reproduced many of the large scale observed features of the magnetosphere and even led to the discovery of others. In recent years they frequently are used help interpret observations during magnetospheric storms and substorms but with only limited success. Several factors limit the large scale models. While single fluid MHD models solve the continuity equations and Maxwell’s equations they limit the transport. They are solved on a finite grid and frequently don’t resolve the steep gradients in the magnetosphere. Most importantly the solutions require knowledge of the boundary conditions upstream in the solar wind and at the ionosphere. In this talk we will consider the effects of these boundary conditions. We will show that the solar wind has structures on the scale of the magnetopause which can greatly influence the solutions and that the model results can be very sensitive to the ionospheric conductance which is not well known.