A team of researchers, led by Dr. Pasko, has made significant breakthroughs in understanding lightning initiation and gamma-ray flashes. Their model, Photoelectric Feedback Discharge, simulates conditions that replicate the observations made in thunderclouds.
The research revealed how electrons accelerated by strong electric fields produce X-rays as they collide with air molecules, leading to an avalanche of electrons that initiate lightning. The team also explained how photoelectric events occur and what conditions need to be present for these events to take place.
According to Dr. Pervez, the model was used to match field observations collected by other research groups using ground-based sensors, satellites, and high-altitude spy planes. By comparing their results with previous modeling and observation studies, the team confirmed their explanation of lightning initiation.
The researchers also uncovered why terrestrial gamma-ray flashes are often produced without visible flashes of light or radio bursts. They found that high-energy X-rays produced by relativistic electron avalanches can generate new seed electrons driven by the photoelectric effect, rapidly amplifying these avalanches.
This discovery explains why gamma-ray flashes can emerge from source regions that appear optically dim and radio silent. The research was conducted by a team of experts, including Dr. Pasko, Dr. Pervez, and several professors from universities in France and the Czech Republic.
The U.S. National Science Foundation, Centre National d’Etudes Spatiales (CNES), Institut Universitaire de France, and Ministry of Defense of the Czech Republic supported this research.
Source: https://www.psu.edu/news/engineering/story/bolt-born-atmospheric-events-underpinning-lightning-strikes-explained