Students from St Mary's Catholic High School with Orbyts Fellows Emily Grant and Kendra Gilmore from Northumbria University have undertaken a study of the Earth's magnetosphere, specifically focusing on the behaviour of electrons within and outside the plasmasphere. Utilising data from the Van Allen Probes, a pair of spacecraft launched between 2012 and 2019 to investigate particle dynamics in Earth's radiation belts, the students have built a statistical picture of electron number density and the ratio of electron plasma frequency to gyrofrequency (ω_pe / ω_ce).

The magnetosphere, a region where the Earth's magnetic field dominates and shields the planet from solar winds and cosmic radiation, plays a crucial role in safeguarding our atmosphere. Within this protective bubble lie the radiation belts, toroidal regions rich in high-energy electrons and protons that trap solar wind particles. Closer to Earth, the plasmasphere, a dense, cold plasma region, acts as a reservoir for plasma originating from the ionosphere and influences the nighttime ionosphere.

The research involved calculating the median electron number density and the median ratio of ω_pe / ω_ce using L* values (distance from Earth), magnetic latitude (MLat), and magnetic local time (MLT). Polar plots were employed to visually represent these densities and ratios across different magnetic local times.

The findings reveal that the median electron number density is largest in the night to dawn sector, and is dependent on magnetic latitude. A smoother change in median number density with L* was observed on the dayside across most plots, with the exception of 0 < MLat < 5, while a more drastic gradient was apparent on the nightside. This is visually supported by the gradual weakening of colour from low to high L* values. Similarly, ω_pe / ω_ce is at its maximum in the midnight to dawn sector, and also shows a dependence on magnetic latitude. These insights contribute to a deeper understanding of wave-particle interactions within the inner magnetosphere!