A Comparison of the Galactic Cosmic Ray Electron and Proton Intensities From 1 MeV/nuc to 1 TeV/nuc Using Voyager and Higher Energy Magnetic Spectrometer Measurements Are There Differences in the Source Spectra of These Particles?

TL;DR

This study compares cosmic ray electron and proton intensities across a wide energy range using Voyager and AMS-2 data, revealing similar source spectra but different low-energy behaviors and a higher total number of accelerated electrons.

Contribution

It provides a detailed comparison of source spectra for electrons and protons, highlighting differences at low energies and estimating their source ratios and total accelerated populations.

Findings

Source spectra for electrons and protons are similar above 10 GV.

Electrons have a much larger total number due to low-energy extension.

Electrons' low-energy escape contributes to intergalactic background.

Abstract

Using Leaky Box Model propagation calculations for H nuclei and a Monte Carlo diffusion propagation model for electrons, starting from specific source spectra, we have matched the observed LIS spectra of these cosmic rays measured by Voyager at lower energies and AMS-2 at higher energies, a range from ~10 MeV to ~1 TeV. The source spectra required are very similar rigidity spectra. Below ~6-10 GV the source spectra for both particles are ~P-2.25 and above 10 GV the spectra are ~P-2.36-2.40. This break in the source spectral index is not seen for He and C nuclei in a match of Voyager and AMS-2 intensities both of which have source rigidity spectra with an index ~-2.24 throughout the entire range of measured energies from ~10 MeV//nuc to ~1 TeV/nuc. The absolute source intensities of electrons and H nuclei are derived and the source ratio of accelerated electrons to H nuclei is between 2-5%. The total number of accelerated electrons is much greater than that for protons, however, because the accelerated electron spectrum extends down to ~1-2 MV rigidity whereas the H nuclei spectrum cannot be observed below ~50-100 MV because of ionization energy loss. Most of these low energy electrons escape from the galaxy forming an intergalactic background.