Sun as a cosmic ray TeVatron

TL;DR

This paper proposes that the quiet Sun can accelerate cosmic rays to TeV energies, explaining recent gamma-ray observations and challenging the traditional galactic cosmic ray origin model, with future validation via neutrino detection.

Contribution

It introduces a novel model where the quiet Sun accelerates cosmic rays to TeV energies, explaining gamma-ray emissions and impacting cosmic ray origin theories.

Findings

Gamma-ray flux exceeds theoretical expectations from galactic cosmic rays.

Spectral slopes of gamma-ray emissions differ from galactic cosmic ray spectra.

Future neutrino observations could confirm the model.

Abstract

Very recently, HAWC observatory discovered the high-energy gamma ray emission from the solar disk during the quiescent stage of the Sun, extending the Fermi-LAT detection of intense, hard emission between 0.1 - 200 GeV to TeV energies. The flux of these observed gamma-rays is significantly higher than that theoretically expected from hadronic interactions of galactic cosmic rays with the solar atmosphere. More importantly, spectral slope of Fermi and HAWC observed gamma ray energy spectra differ significantly from that of galactic cosmic rays casting doubt on the prevailing galactic cosmic ray ancestry model of solar disk gamma rays. In this work, we argue that the quiet Sun can accelerate cosmic rays to TeV energies with an appropriate flux level in the solar chromosphere, as the solar chromosphere in its quiet state probably possesses the required characteristics to accelerate cosmic rays to TeV energies. Consequently, the mystery of the origin of observed gamma rays from the solar disk can be resolved consistently through the hadronic interaction of these cosmic rays with solar matter above the photosphere in a quiet state. The upcoming IceCube-Gen2 detector should be able to validate the proposed model in future through observation of TeV muon neutrino flux from the solar disk. The proposed idea should have major implications on the origin of galactic cosmic rays.