Modeling the Response of the Thermosphere and Ionosphere to an Extreme Space Weather Event

The sequence of physical process in the thermosphere and ionosphere during a geomagnetic storm are thought to be well understood. The physics-based coupled models, however, have been designed and somewhat tuned to simulate the response to events that have been observed in the last two solar cycles, such as the Halloween storm in 2003. For an extreme solar storm, it is unclear if the response would be a natural linear extrapolation of the response to more modest event or if non-linear processes would begin to dominate. A numerical simulation has been performed with the CTIPe coupled thermosphere ionosphere model to quantify the likely response to a extreme space weather, more attune to the Carrington type of event in 1859. The solar wind drivers of the system have been estimated so the total energy injection into the upper atmosphere can be quantified. However, there is still significant uncertainty in quantifying some of the other driver-response relationships such as the magnitude and shielding time-scale of the penetration electric field, the possible feedback to the magnetosphere, and the amount of nitric oxide production. Within the limits of uncertainty of the drivers, the magnitude of the response will be quantified and possible non-linear feedback will be elucidated.