GEM: Radial Transport Processes at Earth, Jupiter, and Saturn

Magnetospheres are cavities carved out in space by a magnetic field. In the case of Earth, Jupiter, and Saturn, the cavity is generated by the planet's intrinsic magnetic field. One of the grand challenge problems in magnetospheric physics and space weather-related studies is the transport of plasma (i.e., ionized gas) into or out of a magnetosphere. At Earth, the solar wind (supersonic plasma) enters and fills the magnetosphere. At Jupiter and Saturn, sources of plasma from Io and Enceladus, and their respective moons must be transported outward from the inner magnetosphere and into the solar wind. Whether transport operates "inside out" or "outside in," the problem is ubiquitous in planetary magnetospheres. This study will compare the fundamental transport physics at Earth, Jupiter, and Saturn and will advance the field of magnetospheric physics by studying basic physical processes over a broad range of conditions to better understand the terrestrial space environment, which is critical for understanding space weather and the protection of, e.g., space-based assets. The project will support a graduate student and provide research opportunities for undergraduate students at the University of Alaska Fairbanks (UAF). The team will also support public outreach through UAF's planetarium project, providing scientific content on the aurora at Earth, Jupiter, and Saturn. Giant planet magnetospheres (e.g., Jupiter and Saturn), due to their size, multi-body nature and rotational dynamics are some of the solar system's most complicated and least understood magnetospheres. Yet their internally driven nature makes them an ideal laboratory to study fundamental plasma processes. This proposal aims to compare radial transport at Earth, Jupiter, and Saturn. In particular, the team focuses on conditions similar to all three magnetospheres – the transition from dipole to stretched magnetic field topology – emphasizing the fundamental processes that lead to density structure while conserving magnetic flux. The team will conduct high-resolution global simulations (Grid Agnostic MHD for Extended Research Applications: GAMERA) to quantify particle transport throughout the magnetosphere further. Information theory will be used to establish causality pathways to understand global-scale dynamics leading to local time asymmetry. The project outcome will elucidate the basic transport (mass, momentum, energy, and magnetic flux) processes associated with local-time and radially-dependent flows and magnetodisc structure. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.