Space is never empty. While often visualized as a vacuum separated from Earth by the Karman line, the near-Earth environment is actually a dynamic reservoir of relativistic particles that actively interact with the planet below. In this seminar, I will discuss how the Van Allen radiation belts act not just as a hazard for satellites and astronaut exploration, but as a source of "top-down" forcing that leeches energy deep into the upper and middle atmosphere. During magnetic storms, these highly relativistic space radiation precipitate well below the edge of space, driving ionization as well as producing NOx/HOx species and catalyzing ozone destruction, thus, potentially altering regional weather or climate dynamics.

I will explore the physics governing this coupling, focusing on self-limiting mechanisms in which energetic electrons drive plasma whistler waves that subsequently scatter and constrain the particle population. I will present recent evidence showing how this fundamental plasma process acts as a natural "safety valve," capping natural and artificially created radiation intensity by scattering particles into the atmosphere, thus effectively trading satellite safety for atmospheric energy input.

To fully resolve these dynamics, we must move beyond the era of single-point satellite measurements. I will discuss my work developing next-generation miniaturized particle detectors, which allow for the "pixelation" of geospace via distributed satellite networks. I will conclude by presenting results from a student-led balloon mission launched during the historic May 2024 superstorm, carrying a prototype of this detector and demonstrating how hands-on hardware development can simultaneously advance fundamental physics, train the future space workforce, and close the observational gap in our understanding of the Earth system.

*Refreshments: 10:30 - 11:00 AM (Atrium)