Self-consistent modeling of the auroral ionosphere-thermospher : how does sever space weather affect low-earth orbiting satellites?

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The main objective of this research program is to investigate how solar activity affects the Earth's upper atmosphere at high latitudes. In particular, this program will set out to self-consistently model and explore the ionospheric-thermospheric response to extreme solar activity and study how Low-Earth Orbiting satellite (LEOs) can be affected by these changes. Recent studies using the Space Surveillance Network Two-Line Element sets has shown that solar activity has a detectable influence on the altitude of orbiting satellites. In particular, it has been observed that the rate-of-change of the altitude of so-called "dead satellites" varies in a similar way as the rate-of-change in the F10.7 solar flux index and Ap index. Using "dead satellites" allows us to neglect changes in the altitude that are due to maneuvers by the satellite operator. As a result, any changes in the orbital parameters can be considered to be due to changes in the thermospheric density, the thermospheric winds or a combination of both. The novelty in our approach is that we will use a coupled thermospheric-ionospheric model that has been recently developed at RMC to model the space environment in a self-consistent manner. The model is a two-dimensional time-dependent code that computes the temporal evolution of the number densities of the principal thermospheric and ionospheric species, their temperatures, and the field-aligned velocities of the ions and electrons. The temporal evolution of the electric potential, the electric fields, the current densities and the conductivities of the ionospheric-thermospheric system in response to variations in the particle precipitation can be computed. These simulations will serve as input for orbital propagation subroutines allowing us to model the orbit of LEOs and the effects of severe solar storms on their orbital parameters.