Theoretical Modeling of the Inner Radiation Belt

Aerospace Corporation, El Segundo CA

Investigators

Abstract

This project will use a software toolkit developed at CERN and referred to as GEANT4. The GEANT4 software will be applied to the interaction of neutrons with the atmosphere. The interaction of cosmic rays with the atmosphere generates albedo neutrons. The atmospheric response as a function of input cosmic ray energy and composition will be determined. The response function will then be convolved with the cosmic ray energy spectrum, which has a solar cycle dependence, to obtain the albedo neutron flux as a function of time. The decay of the albedo neutrons produces the proton content of the Earth's inner radiation belt. The neutron flux can therefore be converted to a model of the energy and density of the protons in the inner belt. The model results will be compared with proton data obtained by the AMPEX satellite over the most recent solar cycle. Agreement between the model and the data will validate the GEANT4 toolkit as a framework for further space weather modeling of the inner radiation belt.