Searcharxiv⌕ Search

arXiv subjects

R. Muscheler

Publications and source records attributed to R. Muscheler.

2 recordsLinked to original sources
arXiv2026

36Cl Concentrations from Polar Ice Cores Set New Constraints on the Carrington Event

The Carrington event of 1859 CE is considered as one of the largest geomagnetic storms of the observational era, and often used as a benchmark for a worst-case scenario. Yet, there exists no robust evidence of an associated solar energetic particle event of a significant magnitude, based on measurements of cosmogenic radionuclides 10Be and 14C from ice cores and tree rings, respectively. In this study, we present two 36Cl records from Greenland with 2-year and 4-year resolution from the EGRIP and NGRIP ice-core sites, together with semi-annual 10Be data from EGRIP, as well as annual 10Be and 36Cl concentrations from the Dome Summit Site, Law Dome, East Antarctica. We observe no significant 36Cl concentration increase around 1859 CE in the three records. This allows us to rule out an extreme solar energetic particle event hitting Earth associated with the Carrington event in terms of fluence above 30 MeV. Based on these ice core 36Cl measurements, we can suggest two scenarios: i) a soft SEP event with a maximum fluence above 30 MeV up to three times larger than any Space Age event or, ii) the possibility that there was no Earth-bound SEP event.

astro-ph.SR↗
arXiv2026

Radiation doses during extreme solar energetic particle events

Ions and electrons accelerated to high energies during flares and coronal mass ejections at the Sun may escape the solar atmosphere and, guided by the interplanetary magnetic fields, propagate through space to near-Earth locations. These Solar Energetic Particles (SEPs) can be detected directly by spacecraft instrumentation. The highest energy SEPs may also propagate through the geomagnetic field and precipitate to low atmospheric heights, producing secondary particles including neutrons and protons that trigger the formation of cosmogenic radionuclides. The space weather effects associated with the SEP ion population (for the most part protons) consist principally of radiation risk to aviation, humans in space and spacecraft. This paper focusses on the risks to aviation and astronauts and emphasizes how the parameters of the SEP event, including fluence and spectrum, affect radiation doses. Space weather effects for events that took place in recent decades, for which a large body of measurements and models exist, are discussed. SEP events of extreme magnitudes, such as those extrapolated from radionuclide data from the distant past are then considered and first estimates of the associated radiation at aviation altitudes and in space presented. These are worst-case estimates derived within the assumption that the radionuclide spike was caused by a single SEP event and that the particle spectrum and geomagnetic conditions were the same during all events.

astro-ph.SR↗