The National Science Foundation (NSF) has awarded Assistant Research Scientist/Engineer David Hartley a $345,680 grant to study how two types of plasma waves, called chorus and hiss, impact the Earth's radiation belts. These waves can energize particles to damaging levels as well as cause particles to precipitate into the atmosphere, processes that pose risks to satellites, astronauts, and airplanes flying over the poles.

Typically, a boundary called the plasmapause is used to separate chorus and hiss waves. However, this boundary is often blurry, causing the waves to overlap spatially. This project aims to study these mixed regions, called plasmasphere-plasmatrough transition regions, to understand their impact better. It has been shown that these transition regions occur about half of the time. Data from these periods are often ignored in studies, leading to biased models that only consider times when the boundary is sharp. By creating new models that include both clear and unclear boundaries, the project will improve our understanding of radiation belt dynamics.

This project is a collaboration between the University of Iowa, the University of Colorado, Orion Space Solutions (an Arcfield Company), and the College of St. Scholastica.