The Impact of Extreme Space Weather Events on Habitability

The central question driving this dissertation is: what is the impact of an extreme SWE event on Earth’s habitability? To give an answer, this Thesis examines the entire cause-effect chain underlying Space Weather processes. The second chapter of this dissertation focuses on solar flares, presenting a statistical analysis of their temporal and energetic properties over the last four solar cycles, from SC21 to SC24. Particular attention is given to the characterization of the most intense X-class flares, testing the hypothesis that the intensity of a flare increases with the elapsed time since the previous event. This suggests the existence of an energy storage and release mechanism within the solar atmosphere. In this Thesis, we test this hypothesis in anticipation of the solar maximum, when solar activity is at its peak. The third chapter investigates the role of Coronal Mass Ejections (CMEs), with a focus on two major events that caused intense geomagnetic storms in June 2015 and September 2017. Specifically, the study examines plasma transport mechanisms driven by Kelvin-Helmholtz and Tearing Mode instabilities, which drive magnetic reconnection at the magnetopause. A key objective is to determine whether the intensity of SWE events, in terms of CME speed, correlates with the development of these instabilities, inferring that faster CMEs enhance the conditions for their formation. Subsequently, the dissertation explores the impact of Solar Energetic Particles (SEPs) on Earth’s atmosphere. Unlike CMEs, which predominantly disturb the geomagnetic field, SEPs generate radiation storms capable of altering atmospheric chemistry. This analysis evaluates whether extreme SEP fluxes, such as those associated with the most intense recorded event (the Carrington event), could significantly modify the concentration of greenhouse gases like N2O, potentially leading to a sustained increase in global surface temperature. The purpose of this investigation is to assess whether such mechanism could contribute to resolving the Faint Young Sun Paradox. In addition, the dissertation quantifies the radiation dose reaching Earth’s surface during a Carrington-like SEP event, identifying secondary particles generated in the atmosphere. These results provide critical insights into the potential effects of such events on surface habitability and human health the study concludes with an analysis of the CUBE satellite mission. By performing a link-budget analysis based on the spatial configuration of satellites positioned in various regions of Earth’s magnetosphere, this work evaluates their capability to collect critical data during extreme CME events, including measurements of magnetic reconnection processes. Through the integration of statistical, theoretical, and numerical approaches, this dissertation provides a comprehensive evaluation of the multifaceted impacts of extreme SWE events. It offers new perspectives on their implications for Earth’s habitability, technological systems, and future observational missions.