Cosmic Muon Ionization Enhances Warm Rain Formation: A High-Energy Physics Approach to Atmospheric Microphysics

This research explores how ionization caused by atmospheric muons influences the enhancement of warm rain production, particularly through the electrostatic collision-coalescence processes that occur within cloud droplets. By applying methods from high-energy physics, we evaluate muon fluxes concerning geomagnetic latitude and altitude to precisely calculate ion pair generation using the Bethe-Bloch formula. This investigation includes easily ionizable gases such as nitrogen (N₂), oxygen (O₂), argon (Ar), and carbon dioxide (CO₂), along with their respective W-values. The ions produced and the activation of sodium chloride (NaCl)-based cloud condensation nuclei in supersaturated conditions, as outlined by Köhler theory, leads to the creation of electrically charged cloud droplets that grow in size through vapor diffusion, thus increasing the coalescence rate due to electrostatic forces. The electric field is determined self-consistently through Poisson's equation. We integrated meteorological data concerning temperature, pressure, and relative humidity. Our results reveal that muon-induced ionization significantly speeds up raindrop formation by facilitating coalescence among charged droplets. This highlights the importance of atmospheric ionization as a crucial microphysical factor within warm cloud systems. This study emphasizes the potential of high-energy physics methodologies in exploring fundamental geophysical questions and suggests a framework for examining the effects of cosmic rays on weather phenomena which can lead to rain stimulation by using cosmic muons instead of artifical methods in future.