The Relationship Between Coronal Mass Ejection Intensity and Cosmic Ray Flux
JURPA 2026 Cover Image.
Abstract. This investigation examines the relationship between coronal mass ejection (CME) intensity and cosmic ray muon flux in North America using ground-level detectors. CMEs carry charged particles that interact with Earth’s magnetic field, which deflects incoming galactic cosmic rays. As these cosmic rays reach the atmosphere, they generate showers of secondary particles, including muons, which can be measured by ground detectors. However, atmospheric pressure also influences muon flux. In this work, a method of correction was developed and tested that significantly reduced this barometric shielding effect. This correction enabled clearer characterization of muon flux changes due to the May 2024 CME. Analysis of corrected data using multiple detectors in the United States found an inverse relationship between CME intensity and cosmic ray muon flux consistent with a Forbush decrease pattern. Additionally, the impact of statistical error on the visibility of CME-induced effects was assessed.
