The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997 to 2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework.

Boschini, M., Della Torre, S., Gervasi, M., Grandi, D., Jóhannesson, G., La Vacca, G., et al. (2018). HelMod in the Works: From Direct Observations to the Local Interstellar Spectrum of Cosmic-Ray Electrons. THE ASTROPHYSICAL JOURNAL, 854(2), 1-10 [10.3847/1538-4357/aaa75e].

HelMod in the Works: From Direct Observations to the Local Interstellar Spectrum of Cosmic-Ray Electrons

Gervasi, M;Grandi, D;La Vacca, G;Pensotti, S;Rozza, D;Tacconi, M
2018

Abstract

The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997 to 2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework.
Articolo in rivista - Articolo scientifico
cosmic rays; diffusion; elementary particles; interplanetary medium; ISM: general; Sun: heliosphere;
cosmic rays – diffusion – elementary particles – interplanetary medium – ISM: general – Sun: heliosphere
English
1
10
10
Boschini, M., Della Torre, S., Gervasi, M., Grandi, D., Jóhannesson, G., La Vacca, G., et al. (2018). HelMod in the Works: From Direct Observations to the Local Interstellar Spectrum of Cosmic-Ray Electrons. THE ASTROPHYSICAL JOURNAL, 854(2), 1-10 [10.3847/1538-4357/aaa75e].
Boschini, M; Della Torre, S; Gervasi, M; Grandi, D; Jóhannesson, G; La Vacca, G; Masi, N; Moskalenko, I; Pensotti, S; Porter, T; Quadrani, L; Rancoita, P; Rozza, D; Tacconi, M
File in questo prodotto:
File Dimensione Formato  
2018_ApJ_GALPROP_electrons.pdf

accesso aperto

Dimensione 847.93 kB
Formato Adobe PDF
847.93 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/185721
Citazioni
  • Scopus 38
  • ???jsp.display-item.citation.isi??? 33
Social impact