A new break near 10 TeV in the energy spectrum of protons according to data from space-based instruments: astrophysical interpretation

TL;DR

Recent space-based measurements reveal a proton energy spectrum break near 10 TeV, suggesting local sources and propagation effects in a fractal galactic medium, challenging standard cosmic ray models.

Contribution

This work models the spectral break using nonclassical diffusion in a fractal galactic medium, identifying a local source at 120 pc with specific age and spectrum.

Findings

Break at ~10 TeV explained by a local source 120 pc away.

Source has an age of approximately 500,000 years.

Proton spectrum exhibits a soft power-law behavior before and after the break.

Abstract

Recent experimental data from space-based instruments of the DAMPE and CALET collaborations have shown that the energy spectrum of protons has a new feature, a break in the $\sim 10$ TeV region. In this energy range, the spectrum index of the observed particles varies from $-2.6$ to $-2.9$. The purpose of this work is to establish the local sources's position and age that determine this break, the index of the proton generation spectrum in them, as well as the astrophysical interpretation of the results obtained in the DAMPE and CALET experiments. Within the framework of the model of nonclassical diffusion of cosmic rays developed by the authors, which has break due to the propagation of particles in a sharply inhomogeneous (fractal type) galactic medium, it is shown that break in this energy range is formed by tevatron located at a distance of $\sim 120$ pc from the Earth. These source, whose age is $\sim 5 \cdot 10^5$ years, generate particles with a spectrum index $\sim 2.7$. The power-law behavior of the proton spectrum before and after the break, soft spectrum of particles generation in the source, first obtained in the DAMPE and CALET experiments, should be considered as an indication of the need to revise the standard paradigm accepted today about the sources of cosmic rays, mechanisms of particle acceleration in them and particles propagation in the Galaxy.