Insights into Sunward Streaming Energetic Particle Formation and Evolution through Multi-Point Observations

Solar energetic particles can disrupt satellites, communications, navigation, and power systems, and they can pose risks to astronauts and spacecraft. This project seeks to improve understanding of how energetic particles are transported and accelerated from the Sun through interplanetary space, especially during events when particles stream back toward the Sun and affect Earth. The work will contribute to the scientific basis for space weather forecasting and mission planning. The project will support an early-career researcher and provide summer research opportunities for undergraduate students. This project will investigate how energetic particles from both solar and heliospheric sources form and evolve, with a particular focus on particles streaming sunward in the inner heliosphere. The team seeks to identify particle sources and formation mechanisms, including how solar activity may contribute to their solar cycle dependence; characterize the radial and longitudinal evolution of sunward-streaming energetic particle events; and examine the factors that influence differences between sunward-streaming energetic protons and electrons. The analysis will use spacecraft and ground-based datasets obtained during the past solar cycle, including the NSF-funded Expanded Owens Valley Solar Array (EOVSA). The study will leverage advances in anisotropy characterization and multi-platform observations to examine sunward-streaming energetic particles across one solar cycle. 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.