Energy Spectra of Secondary Particles Induced by Solar Energetic Proton Events and Magnetospheric Effects

TL;DR

This study analyzes secondary cosmic ray energy spectra from solar events, revealing differences between magnetospheric effects and ground-level enhancements, and proposes new ground-based diagnostic tools for early warning of solar hazards.

Contribution

The paper provides a detailed comparison of ME and GLE spectra using multi-instrument data and simulations, offering new insights into their origins and detection methods.

Findings

MEs caused by galactic protons below geomagnetic cutoff during storms

GLEs involve high-energy solar protons reaching sea level

SEVAN data enhances early warning capabilities

Abstract

We investigate the energy spectra of secondary cosmic ray particles associated with two distinct solar events: the magnetospheric effect (ME) of 5 November 2023 and ground-level enhancement (GLE 74) of 11 May 2024. Using data from the SEVAN and Neutron Monitor networks and energy release histograms from particle spectrometers, we reconstruct spectra and identify key differences between ME and GLE. CORSIKA-based simulations reveal that MEs are caused by galactic protons below geomagnetic cutoff rigidities (Rc = 7.1 GV at Aragats) penetrating the magnetosphere during geomagnetic storms, leading to localized flux enhancements at mountain altitudes but not at sea level. In contrast, SEP events initiated by GLEs can involve high-energy solar protons (>10 GeV), producing secondaries that reach sea level at middle latitudes. We present integral energy spectra and spatial correlation of detector responses, demonstrating that SEVAN's energy-resolved data offer new diagnostic tools for identifying hard-spectrum SERs. Our results refine the definition of ME and suggest a strategy for early warning of hazardous solar particle events based on real-time ground-based observations.