Raindrop formation in a thunderstorm mimicking environment under non-uniform electric field

Abstract

The rapid formation of raindrops within thunderstorm clouds is significantly influenced by the synergistic effect of non-uniform electric fields and charge, which facilitates the collision and growth of droplets. This phenomenon forms the theoretical foundation for charged particle catalytic artificial rainfall technology. Despite this, the precise mechanism by which these factors enhance droplet collision and growth remains elusive. In this study, we endeavored to elucidate this mechanism by constructing a non-uniform electric field to emulate the conditions within a lightning environment. We introduced charged–neutral droplet pairs and systematically investigated the impact of electric field gradient and charge on droplet collision characteristics, specifically the likelihood and frequency of collisions, under various reference field strength conditions. Our findings indicate that when the reference field strength is below 1.75 × 105 V · m−1, the decaying gradient electric field and the increase in charge significantly enhances the likelihood of droplet collisions. Conversely, a higher electric field gradient is associated with a decreased collision frequency, while a higher charge has a positive effect on this frequency. These insights not only contribute to a deeper comprehension of the mechanisms by which non-uniform electric fields and charge promote droplet collision and growth within thunderstorm clouds but also offer theoretical underpinnings for the optimization of charged particle catalytic artificial rainfall technology.