For the first time in history, scientists have used lasers to tame lightning and direct it into new trajectories — a breakthrough that could lead to improved defenses against these dangerous strikes from the sky, The Vice reports.
The idea of deflecting lightning with lasers has been around for decades, but an experiment that took place on Switzerland's Säntis mountain in the summer of 2021 is the first to finally demonstrate the process in the field.
The advent of metal lightning conductors has reduced the risk of victims from lightning, but the protective radius of these devices is limited to their immediate proximity. Firing laser pulses into the sky could theoretically extend the virtual shield around much larger areas, but attempts to implement the technology have been unsuccessful — until now.
Scientists led by Aurélien Houard, a researcher at ENSTA at the Ecole Polytechnique Paris, have provided the first field result that experimentally demonstrates laser-guided lightning, an important step forward in the development of laser lightning protection for airports, launch pads or large infrastructure facilities, according to the study published in the Nature Astronomy journal.
Houard and his colleagues successfully guided four “upward” lightning discharges, which are bolts that strike up from the ground, with laser pulses shot into the sky over Säntis Mountain. High-speed cameras captured one such interception, showing that the lasers were able to direct a lightning strike over 50 meters away. The obtained data indicate that laser lightning rods can potentially protect infrastructure within a radius of 800 meters at an altitude of several hundred meters.
"Lightning has fascinated and terrified humankind since time immemorial. Based on satellite data, the total lightning flash rate worldwide — including cloud-to-ground and cloud lightning — is estimated to be between 40 and 120 flashes per second, causing considerable damage and casualties,” the researchers say. “Here we present the first demonstration that laser-induced filaments — formed in the sky by short and intense laser pulses — can guide lightning discharges over considerable distances. We believe that this experimental breakthrough will lead to progress in lightning protection and lightning physics.”
The researchers achieved this result by installing a laser near a telecommunications tower on a mountain that is a hot spot for lightning strikes. During a thunderstorm, the device fired laser pulses into the sky, a process that turns particles and molecules in the air into plasma structures.
Houard and his colleagues used a variety of techniques to show that this plasma can attract and guide lightning discharges, though the team was only able to redirect upward strikes, which are far more common at Säntis Mountain than the more familiar downward sky-to-ground strikes. To that end, the team hopes that future experiments will finetune this promising technology so that it can be implemented over critical infrastructure.