Forecasting and Remote Sensing Outer-belt Relativistic Electrons from Low-Earth-Orbits

Abstract:

Relativistic (~MeV) electrons trapped in the Earth’s outer radiation belt present a highly hazardous radiation environment for spaceborne electronics. Thus developing a forecasting capability for MeV electron levels as well as understanding the physics have been deemed critical for both space research and industry communities. In this work, we first demonstrate that a high cross-energy, cross-pitch-angle and time-delayed coherence (with correlation values up to ~0.85) exists between the trapped MeV electrons and precipitating >~100s KeV electrons—observed respectively by Van Allen Probes and NOAA POES satellites in very different orbits—by conducting a survey on measurements from both high- and low-altitudes. Then, based upon the coherence, we further test the feasibility of using linear prediction filter models, driven by POES observations from low-Earth-orbits (LEOs), to provide event-specific predictions of the energization of MeV electrons during geomagnetic storms, as well as the evolving distributions of MeV electrons afterwards. These models predict MeV electron levels with high fidelity and have performance efficiency of ~0.74 (0.66) for 5-hour (1-day) forecasts. Last, after further investigating the high coherence by using pitch-angle resolved electron data from Van Allen Probes, we provide our explanations based upon case calculations from an analytic wave-particle resonance model. Results from this study reveal new knowledge of radiation belt dynamics, add new science significance to a long existing LEO space infrastructure, and provide practical and powerful tools to the whole space community.