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Fitting the Galactic Electron Spectrum Measured by Voyager at Low Energies and also by CALET/AMS-2 at High Energies Using a Monte Carlo Diffusion Model for Electron Propagation - One Spectrum Fits All

2018/10/25 by Webber, W. R., Quenby, J., Harrison, T. +2
#FOS: Physical sciences #Space Physics (physics.space-ph)

paper · doi:10.48550/arxiv.1810.11100

Abstract

In this paper we compare galactic electron spectra measured up to TeV energies by AMS2 and CALET and that measured by Voyager at the lowest energies down to 1 MeV with that calculated using a Monte Carlo diffusion model for electron propagation in the galaxy. The observations and calculations at both ends of the electron spectrum, differing by a factor ~106 in energy, can be matched to within a few percent with a minimal set of assumptions. This includes an electron spectrum which has an index increasing from ~2.1 at the lowest energies to 2.4 at ~1 TeV, along with a diffusion coefficient that remains essentially constant below ~1.5 GV above which it becomes P0.45. The Monte Carlo calculations indicate that the lowest and highest energy electrons originate within a local region near the galactic plane of size, less than L where L is the thickness of the trapping region. The remarkable agreement to within a few percent between the calculations and measurements from 20 GeV up to ~1 TeV also indicates that there are no individual sources greater than 10-20 percent of the Monte Carlo calculated background that are contributing to the observed electron intensity in this energy range.

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