Energy deposition in planetary and exoplanetary atmospheres induced by cosmic rays
Abstract
Cosmic rays can significantly alter the abundances of certain species in the upper layers of planetary atmospheres, especially in terms of their biosignatures. To fully understand the extent of this effect, it is essential to accurately model the interactions of cosmic rays with planetary magnetic fields. We used the CosmicTransmutation code to study the effect of a planetary magnetic field on the flux of galactic cosmic rays and stellar energetic particles. We found that both particle sources are significantly affected by magnetic fields, even though the effects are different due to the varying energy ranges that characterize each source. The stellar energetic particle energy flux is significantly higher for an Earth-like planet with no magnetic field, but with a magnetic field of 30\,μT or higher, the energy flux of the two sources becomes comparable. We find that the atmospheric pressures the cosmic rays reach are significantly lower than those found in previous studies using simpler models and that the effect of the atmospheric composition on this outcome is small. We found similar results using the model for the exoplanet K2-18b, even though the radius is significantly larger than Earth's. Because the two cosmic ray sources cover different energy ranges and are affected by the magnetic field in different ways as a result, both sources should be considered. Future studies should focus on combining an accurate modelling procedure of the interaction between cosmic rays and planetary magnetic fields with atmospheric chemistry models. This will require general circulation models to capture the latitudinal and longitudinal dependencies in full.
Versions
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BibTeX
@misc{polman2026energy,
title = {{Energy deposition in planetary and exoplanetary atmospheres induced by cosmic rays}},
author = {Jesse Polman and Ingo Leya},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.10688},
eprint = {2609.10688},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10688},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Energy deposition in planetary and exoplanetary atmospheres induced by cosmic rays
AU - Jesse Polman
AU - Ingo Leya
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.10688
UR - https://arxiv.org/abs/2609.10688
AB - Cosmic rays can significantly alter the abundances of certain species in the upper layers of planetary atmospheres, especially in terms of their biosignatures. To fully understand the extent of this effect, it is essential to accurately model the interactions of cosmic rays with planetary magnetic fields. We used the CosmicTransmutation code to study the effect of a planetary magnetic field on the flux of galactic cosmic rays and stellar energetic particles. We found that both particle sources are significantly affected by magnetic fields, even though the effects are different due to the varying energy ranges that characterize each source. The stellar energetic particle energy flux is significantly higher for an Earth-like planet with no magnetic field, but with a magnetic field of 30\,μT or higher, the energy flux of the two sources becomes comparable. We find that the atmospheric pressures the cosmic rays reach are significantly lower than those found in previous studies using simpler models and that the effect of the atmospheric composition on this outcome is small. We found similar results using the model for the exoplanet K2-18b, even though the radius is significantly larger than Earth's. Because the two cosmic ray sources cover different energy ranges and are affected by the magnetic field in different ways as a result, both sources should be considered. Future studies should focus on combining an accurate modelling procedure of the interaction between cosmic rays and planetary magnetic fields with atmospheric chemistry models. This will require general circulation models to capture the latitudinal and longitudinal dependencies in full.
ER -