Correlation Between Radiation Enhancements at Aviation Altitudes and Energetic Precipitating Electrons

Abstract The campaign of Automated Radiation Measurements for Aerospace Safety (ARMAS) has revealed that relativistic electron precipitation (REP) from the radiation belts can significantly enhance the radiation environment at aviation altitudes, in addition to the well‐known sources of galactic cosmic rays and solar energetic particles. Recent studies using measurements from Van Allen Probes have found that ARMAS radiation doses are closely related to plasmaspheric hiss observed in the inner magnetosphere, which can scatter energetic electrons into the Earth's atmosphere. However, there still lacks a direct comparison between measurements of radiation doses and precipitating electrons. Therefore, in this statistical study, we compare measurements from ARMAS and Polar‐orbiting Observational Environmental Satellites (POES). Out of more than 700 ARMAS experiments conducted between 2013 and 2019, there are 106 conjunction events, in which the POES satellite was close to ARMAS flight in both space and time. We have quantified the correlation between ARMAS‐measured radiation doses and POES‐measured precipitating fluxes at different electron energies. The correlation coefficient is, in general, low for precipitating electrons with energies below MeV, but becomes larger than 0.5 for electron energies above 1.89 MeV, and the largest coefficient is as high as 0.60 for 8.95‐MeV precipitating electrons. The results show that ARMAS measurements are correlated with REP, indicating a potential contribution of relativistic precipitating electrons to the radiation environment at aviation altitudes.