NSF Award
2400284
The Earth’s radiation belts are a dynamic and complex plasma environment. Large amplitude waves can nonlinearly accelerate particles to energies high enough to pose a radiation hazard in the near-Earth space environment. These large amplitude waves are common but only occur in small regions for a short period of time. Therefore, it is unknown if such a drastic but localized acceleration can have an impact on a global scale. By modeling the nonlinear wave-particle interaction in a global scale radiation belt model, this research will conclusively show the importance of these large-scale waves on the whole space environment. The research will promote the development of two early-career researchers. Additionally, undergraduate students at a minority-serving institution will be trained as an integral part of this project.<br/><br/>The physics of wave-particle interactions in the Earth’s radiation belts is well understood in the linear and quasilinear regimes, but large amplitude waves create a complex nonlinear problem. Significant theoretical and computational work has been done to understand how nonlinear wave-particle interactions can efficiently energize or pitch angle scatter high-energy electrons. As successful as local studies of nonlinear wave-particle interactions have been in explaining the micro-scale physics of a particle in a large amplitude wave, it has yet to be demonstrated that these nonlinear effects lead to global, macro-scale changes in the radiation belts. In this study, we will use theory, modeling, and data analysis to answer the fundamental science question: Do nonlinear wave-particle interactions affect the radiation belts on a global scale? This will be done by calculating advection and diffusion coefficients from nonlinear wave-particle interactions that can be directly included in the K2 radiation belt model. K2 is a global scale radiation belt model based on the stochastic differential equation (SDE) framework and accurately captures wave-particle interactions at an individual particle level. By simulating real events with K2, the sensitivity of the whole radiation belt system to localized large amplitude waves can be quantified.<br/><br/>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.
