ABSTRACT

Eruptive events on the Sun such as solar flares and coronal mass ejections (CMEs) can greatly energize electrons, protons and heavy ions. When these "solar energetic particles" (SEPs) interact with the Earth, they are a potential space weather hazard. They can have adverse impacts on avionics, satellites, and astronauts. Forecasting SEP events is a challenge because they are unpredictable and the particles can arrive at Earth within minutes to hours of the solar event. To mitigate the harmful effects due to SEPs on our technology-dependent society, we need a thorough understanding of how such energetic particles are transported and accelerated in the solar system, particularly in near-Earth space. Due to the nature and scale of the problem, such an understanding requires collaborative efforts from researchers in multiple disciplines, including solar physics, space physics and geospace sciences, plasma physics and particle physics. In this project, a multidisciplinary team from the University of Alabama in Huntsville (UAH), University of Michigan (UM), University of Wisconsin at River Falls, and the National Solar Observatory will develop a comprehensive scientific model to understand and forecast SEPs. They will create a web-based SEP forecasting tool hosted by UAH and UM for use by the space weather community. University students and a postdoctoral researcher will have leadership roles in all aspects of the project. The broader impacts of this cutting-edge research effort are thus in its potential to improve societal resilience to a space weather hazard while advancing our nation's expertise in space science and space weather.

This project will develop a comprehensive scientific model to understand and predict how CMEs influence the energetic particle radiation environment in the inner solar system and Earth's magnetosphere, and compare the results with measurements at the Earth's surface. Two widely used models, the Space Weather Modeling Framework (SWMF) and the improved Particle Acceleration and Transport in the Heliosphere model (iPATH) will be coupled. Existing gaps in SWMF and iPATH will be bridged by developing two new models: a machine learning-assisted CME model for the lower solar corona, and a particle tracing model for transport from the Lagrange L1 point into the magnetosphere. The integrated model will provide the ability to simulate the propagation of SEPs from CME launch to signals detected by ground-based neutron monitors, and account for effects on galactic cosmic rays, e.g., the Forbush decrease. Model validation will include comparison with neutron monitor data for a number of ground level enhancements and large SEP events during solar cycles 23 and 24. An integrated SEP/GCR Forecasting Tool will be made openly accessible to the space weather community through a web interface. Daily forecast of the SEP/GCR flux at the L1 point and inside the magnetosphere, as well as neutron monitor flux (when applicable) will be provided at 8-hour intervals. Given the increased interest in Sun-Earth system science, a graduate level course on magnetospheric physics will be developed at UAH. Undergraduate and graduate students and early-career researchers including a postdoctoral scholar will be fully involved in the research and outreach efforts. ANSWERS projects will advance the nation?s STEM expertise and societal resilience to space weather hazards by filling key knowledge gaps regarding the coupled Sun-Earth system.

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.

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