Self-confinement of ultra-high-energy nuclei in cosmic filaments: implications for the UHECR spectrum and composition
Abstract
The spectrum and composition of ultra-high-energy cosmic rays (UHECRs) suggest that the population dominating above the ankle releases particles with an unusual hard spectrum at low rigidity, below the EV scale. In self-confinement scenarios, such an apparent hardening arises from transport: escaping UHECRs generate magnetic turbulence that delays their own release from the magnetized environments surrounding their sources. We extend the self-confinement scenario based on the non-resonant streaming instability to a mixed nuclear composition. We describe the confinement region with an effective leaky-box model including escape, photodisintegration, and secondary production. We then compare the resulting spectrum and composition with Auger measurements and compute the associated cosmogenic neutrino and gamma-ray emission. We find that self-generated turbulence can suppress the escaping flux below the EV scale for source luminosities and magnetic-field coherence lengths compatible with UHECR sources hosted in galaxy clusters and propagating through cosmic filaments. During confinement, heavy nuclei efficiently photodisintegrate, producing secondary protons that contribute below the ankle and help account for the observed composition. The predicted neutrino flux remains compatible with current limits, while the diffuse gamma-ray background provides a potentially strong constraint on the most extreme configurations.
Versions
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BibTeX
@misc{cermenati2026selfconfinement,
title = {{Self-confinement of ultra-high-energy nuclei in cosmic filaments: implications for the UHECR spectrum and composition}},
author = {Alessandro Cermenati and Roberto Aloisio and Carmelo Evoli},
howpublished = {arXiv},
year = {2026},
month = may,
doi = {10.48550/arxiv.2605.14869},
eprint = {2605.14869},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2605.14869},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Self-confinement of ultra-high-energy nuclei in cosmic filaments: implications for the UHECR spectrum and composition
AU - Alessandro Cermenati
AU - Roberto Aloisio
AU - Carmelo Evoli
PY - 2026
DA - 2026/05/14
PB - arXiv
DO - 10.48550/arxiv.2605.14869
UR - https://arxiv.org/abs/2605.14869
AB - The spectrum and composition of ultra-high-energy cosmic rays (UHECRs) suggest that the population dominating above the ankle releases particles with an unusual hard spectrum at low rigidity, below the EV scale. In self-confinement scenarios, such an apparent hardening arises from transport: escaping UHECRs generate magnetic turbulence that delays their own release from the magnetized environments surrounding their sources. We extend the self-confinement scenario based on the non-resonant streaming instability to a mixed nuclear composition. We describe the confinement region with an effective leaky-box model including escape, photodisintegration, and secondary production. We then compare the resulting spectrum and composition with Auger measurements and compute the associated cosmogenic neutrino and gamma-ray emission. We find that self-generated turbulence can suppress the escaping flux below the EV scale for source luminosities and magnetic-field coherence lengths compatible with UHECR sources hosted in galaxy clusters and propagating through cosmic filaments. During confinement, heavy nuclei efficiently photodisintegrate, producing secondary protons that contribute below the ankle and help account for the observed composition. The predicted neutrino flux remains compatible with current limits, while the diffuse gamma-ray background provides a potentially strong constraint on the most extreme configurations.
ER -