A breakthrough in understanding the mysteries of lightning strikes has been achieved by a team of researchers led by Victor Pasko, a professor at Penn State. The study published today reveals the chain reaction that triggers lightning within thunderclouds.
The researchers used mathematical modeling to explain how strong electric fields accelerate electrons into air molecules like nitrogen and oxygen, producing X-rays and initiating a cascade of additional electrons and high-energy photons. This process creates the perfect conditions for lightning bolts to form.
According to Pasko, their findings provide the first precise explanation for how lightning initiates in nature, connecting the dots between X-rays, electric fields, and electron avalanches.
The team used a model called Photoelectric Feedback Discharge, which simulates physical conditions that lead to lightning strikes. They matched field observations of photoelectric phenomena with simulated thunderclouds and confirmed their explanation for X-ray production and radio emissions.
The researchers also explained why some terrestrial gamma-ray flashes are not accompanied by visible light or radio bursts. They found that high-energy X-rays produced by relativistic electron avalanches generate new seed electrons, rapidly amplifying the avalanches and leading to detectable levels of X-rays without accompanying optical or radio emissions.
This study provides a complete explanation for lightning initiation and offers other researchers the opportunity to build upon their work using the available equations in the paper.
Source: https://phys.org/news/2025-07-born-atmospheric-events-underpinning-lightning.html