Research Article

Sun-to-Mud observations of the May and October storms of 2024: impacts on Ireland’s Space Weather

¹ Astronomy & Astrophysics Section, School of Cosmic Physics, Dublin Institute for Advanced Studies, DIAS Dunsink Observatory, Dublin D15 XR2R, Ireland
² School of Physics, Trinity College Dublin, Dublin 2, Ireland
³ Department of Physics, University of Otago, Dunedin 9016, New Zealand

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 9 May 2025
Accepted: 29 September 2025

Abstract

Near the peak of Solar Cycle 25 in 2024, Earth was impacted by two major solar eruptive events which triggered dramatic geomagnetic storm activity. In May 2024, multiple solar eruptive events generated the largest geomagnetic storm since the early 2000s; this was followed by a similar-sized geomagnetic storm in October 2024, driven by a single solar eruptive event. Both storms occurred in the “social media era”, when the widespread use of mobile imaging devices on “smartphones” encouraged the public to go outside and witness the storms, often capturing and sharing photographs; examples local to the island of Ireland are analysed in this study. While the socio-historic impact of the storms was significant, in this manuscript, the sources and effects of the two storms are compared and contrasted. A “Sun-to-Mud” analysis is presented, from the solar origins of the events down to regional electrodynamic effects over the island of Ireland. Results indicate that while the May storm was driven by a compound CME-CME event following a quiet period, the single CME driving the October storm arrived at a magnetosphere primed by previous activity. Both storms exhibit strong solar wind – magnetosphere-ionosphere coupling, and the precursor activity in October demonstrates that the time history of magnetosphere-ionosphere priming is an important factor that influences the ultimate effect of a transient solar-driven event. Locally over the island of Ireland, observations suggest auroral electrojets poleward of local magnetometers, and both events generate remarkable geomagnetically induced currents; these observations are presented along with local auroral photographs.