Data-Model Comparisons of the October, 2002 Event Using the Space Weather Modeling Framework

The September 27 - October 4, 2002 time period has been selected by the Geospace Environment Modeling Ionospheric Outflow focus group for community collaborative study because of its high magnetospheric activity and extensive data coverage. The FAST, Polar, and Cluster missions, as well as others, all made key observations during this period, creating a prime event for data-model comparisons. The GEM community has come together to simulate this period using many different methods in order to evaluate models, compare results, and expand our knowledge of ionospheric outflow and its effects on global dynamics.

This paper presents Space Weather Modeling Framework (SWMF) simulations of this important period compared against observations from the Polar TIDE, Cluster CODIF and EFW instruments. Density and velocity of oxygen and hydrogen throughout the lobes, plasmasheet, and inner magnetosphere will be the focus of these comparisons. For these simulations, the SWMF couples the multifluid version of BATS-R-US MHD to a variety of ionospheric outflow models of varying complexity. The simplest is outflow arising from constant MHD inner boundary conditions. Two first-principles-based models are also leveraged: the Polar Wind Outflow Model (PWOM), a fluid treatment of outflow dynamics, and the Generalized Polar Wind (GPW) model, which combines fluid and particle-in-cell approaches. Each model is capable of capturing a different set of energization mechanisms, yielding different outflow results. The data-model comparisons will illustrate how well each approach captures reality and which energization mechanisms are most important. This work will also assess our current capability to reproduce ionosphere-magnetosphere mass coupling.