"Simulating an extreme space weather storm" |
| Prof. Ramon E. Lopez |
| Dept. of Physics and Space Sciences Florida Institute of Technology |
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Space weather is an increasingly important issue for
our global, technological society. The interagency National Space
Weather Program has as one of its goals the development of predictive
space weather models and the integration of those models into the
forecasting system of the National Weather Service. As a consequence,
the National Science Foundation has established the Center for
Integrated Space weather Modeling (CISM), a Science and Technology
Center, with the scientific goal to develop a set of coupled numerical
simulations extending from the Sun to the Earth. In order for
physics-based numerical simulations to be useful as predictive models
one must have confidence that the essential physics of the situation is
being correctly simulated, and one must also know how well the
simulation results reproduce reality. In this talk I will review how space weather impacts our technology. I will then present some recent results from simulations of the near-Earth space environment using one of the CISM codes, a 3-dimensional simulation of the solar wind interacting with the magnetosphere-ionosphere system. In particular, I will discuss what we have learned from our simulation of an extreme magnetic storm period that occurred at the end of October, 2003. This event allows us to examine a basic physics issue known as the saturation of the polar cap potential, where the electric field that the solar wind can apply to the ionosphere through magnetic reconnection with the magnetosphere is limited, a feature reproduced in the simulation. We have developed a model that explains this saturation effect as a nonlinear relationship between the solar wind electric field and the reconnection electric field during periods when the magnetosphere is being strongly driven by the solar wind. I also will present a quantitative measure of the ability of the simulation to predict when a geosynchronous satellite will be outside the magnetosphere, which is of interest to forecasters. Thus space weather research can be seen to have both basic and applied aspects. |
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