Jim Hogan

Understanding the composition of the atmosphere is integral to understanding the effect humans are having on our atmosphere. Knowing the constituency and density of the atmosphere by altitude gives us insight into what incoming particles are reflected, the quantity of greenhouse gasses within the atmosphere, as well as the likelihood of solar events like aurora borealis. While densities below 40 km above the Earth’s surface can be tracked through weather balloons and above 600 km can be tracked through satellites, the range in between, which contains the ionosphere, thermosphere, and mesosphere, is unable to be measured through either method. The purpose of this research is to develop a model of species density within this region using downgoing and reflected particles measured through satellites. Through the FAST satellite (Fast Auroral SnapshoT Explorer), there are pre-existing datasets of the flux of downgoing and upgoing particles that travel through the ionosphere and return to the satellite or originate from the ionosphere. Using a model particle distribution determined by the MEPT (Magnetospheric Ensemble Particle Tracing) model at 620 km, the forces at play within the Earth’s Ionosphere can be simulated and compared to the FAST satellite data. A goal of our research in the Lysak Space Physics Group is to develop a simulation, known as PADIC (Probabilistic Altitude Dependent Ionospheric Collisional) model, that can accurately recreate these measured particle distributions based on collisional physics. While PADIC still has many interactions in the Earth’s ionosphere to be included, it has been shown to accurately represent some aspects of the physics of the measured distribution.