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Updated: Jun 19, 2026

Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
Inhomogeneity in cosmic ray sources as the origin of the electron spectrum and the PAMELA anomaly
Nir J Shaviv1, Ehud Nakar, Tsvi Piran
1Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract:
We show that inhomogeneity of cosmic ray (CR) sources, due to the concentration of supernova remnants (SNRs) towards the galactic spiral arms, can naturally explain the anomalous increase in the positron/electron ratio observed by PAMELA. We consistently recover the observed positron fraction between 1 and 100 GeV using SNRs as the sole source of CRs. The contribution of a few known nearby SNRs dominates the CR electron spectrum above approximately 100 GeV, leading to the relatively flat spectrum observed by Fermi and to the sharp cutoff observed by H.E.S.S.
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