A Method for Calculating Atmospheric Radiation Produced by Relativistic Electron Precipitation

Abstract

AbstractRadiation safety in the Earth's atmosphere is of particular importance to our living environment, especially at aviation altitudes. Aviation radiation has been long known to originate primarily from the galactic and solar system: galactic cosmic rays and solar energetic protons. Recent flight measurements by the Automated Radiation Measurements for Aerospace Safety experiment have uncovered another potential source for aviation radiation: Relativistic Electron Precipitation (REP) from the Van Allen radiation belts. REP can induce radiation at aviation altitudes through bremsstrahlung X‐ray production, which carries radiation down to the stratosphere and even the troposphere. In this study, using a suite of physics‐based Monte Carlo models, we characterize the effective radiation dose produced at altitudes between ground and low‐Earth‐orbit by relativistic precipitation electrons with energies between 100 keV and 10 MeV. We produce a lookup table of atmospheric radiation production that calculates the expected radiation dose for a given precipitation flux, spectrum, and pitch angle distribution. This lookup table provides results that are consistent with X‐ray measurements during radiation belt precipitation by balloon‐borne instruments in the stratosphere, and can be directly used to convert space‐borne measurements of precipitation fluxes into aviation radiation. This study represents our first attempt toward better understanding of REP's role in the atmospheric high‐altitude radiation environment.