New very local interstellar spectra for electrons, positrons, protons and light cosmic ray nuclei

Abstract

The local interstellar spectra (LIS's) for galactic cosmic rays (CR's) cannot be directly observed at the Earth below certain energies, because of solar modulation in the heliosphere. With Voyager 1 crossing the heliopause in 2012, in situ experimental LIS data below 100 MeV/nuc can now constrain computed galactic CR spectra. Using galactic propagation models, galactic electron, proton and light nuclei spectra can be computed, now more reliably as very LIS's. Using the Voyager 1 observations made beyond the heliopause, and the observations made by the PAMELA experiment in Earth orbit for the 2009 solar minimum, as experimental constraints, we simultaneously reproduced the CR electron, proton, Helium and Carbon observations by implementing the GALPROP code. Below about 30 GeV/nuc solar modulation has a significant effect and a comprehensive three-dimensional (3D) numerical modulation model is used to compare the computed spectra with the observed PAMELA spectra possible at these energies. Subsequently the computed LIS's can be compared over as wide a range of energies as possible. The simultaneous calculation CR spectra with a single propagation model allows the LIS's for positrons, Boron and Oxygen to also be inferred. This implementation of the most comprehensive galactic propagation model (GALPROP), alongside a sophisticated solar modulation model to compute CR spectra for comparison with both Voyager 1 and PAMELA observations over a wide energy range, allows us to present new self-consistent very LIS's (and expressions) for electrons, positrons, protons, Helium, Carbon, Boron and Oxygen for the energy range of 3 MeV/nuc to 100 GeV/nuc.

References in corpus (5)

• The cosmic-ray electron flux measured by the PAMELA experiment between 1 and 625 GeV
• Global cosmic-ray related luminosity and energy budget of the Milky Way
• Measurement of boron and carbon fluxes in cosmic rays with the PAMELA experiment
• High-Energy Gamma Rays from the Milky Way: Three-Dimensional Spatial Models for the Cosmic-Ray and Radiation Field Densities in the Interstellar Medium
• The Galactic Cosmic Ray Electron Spectrum from 3 to 70 MeV Measured by Voyager 1 Beyond the Heliopause, What This Tells Us About the Propagation of Electrons and Nuclei In and Out of the Galaxy at Low Energies

Cited by in corpus (3)

• Diffusive Versus Free-Streaming Cosmic Ray Transport in Molecular Clouds
• Time dependence of the flux of helium nuclei in cosmic rays measured by the PAMELA experiment between July 2006 and December 2009
• Local interstellar spectra and solar modulation of cosmic ray electrons and positrons